Why Large UK Businesses Are Migrating to Cloud in 2026
Large business cloud migration UK is no longer optional. It is a strategic necessity. The pressures driving migration in 2026 are more urgent than ever before.
Windows Server 2019 extended support ends in January 2029. That sounds far away. It is not. Large-scale migrations take 12–18 months to plan and execute. Businesses starting now avoid the rush and the premium pricing that comes with last-minute projects.
Cost pressure is relentless. On-premises infrastructure demands capital expenditure every 3–5 years. Cloud shifts this to predictable monthly operational spending. For a 200-user business, replacing ageing servers can cost £80,000–£150,000. Cloud eliminates that cycle entirely.
Hybrid and remote working is permanent. Staff expect seamless access to files, applications and desktops from anywhere. Cloud delivers this natively. On-premises systems require expensive VPN infrastructure and constant maintenance to achieve the same result.
Scalability matters more than ever. Businesses growing through acquisition or seasonal demand need infrastructure that scales in minutes, not months. Cloud provides exactly that.
Cloud Models Explained for Decision Makers
Before migrating, leadership teams need clarity on what moves where. There are three core cloud service models.
Infrastructure as a Service (IaaS)
You rent virtual machines, storage and networking. You manage the operating system, middleware and applications. This suits businesses lifting existing servers into the cloud with minimal changes.
Examples: Azure Virtual Machines, AWS EC2, file servers, domain controllers.
Platform as a Service (PaaS)
The cloud provider manages the infrastructure and operating system. You deploy your applications on top. This suits development teams and custom line-of-business applications.
Examples: Azure App Service, AWS Elastic Beanstalk, Azure SQL Database.
Software as a Service (SaaS)
Fully managed applications delivered over the internet. No infrastructure to manage at all. Most businesses already use SaaS without realising it.
Examples:Microsoft 365, Salesforce, Xero, HubSpot.
What Typically Moves Where
| Workload | Model | Typical Approach |
|---|---|---|
| File servers | IaaS / SaaS | Migrate to SharePoint or Azure Files |
| SaaS | Exchange Online via Microsoft 365 | |
| Line-of-business applications | IaaS / PaaS | Rehost on VMs or refactor to PaaS |
| Databases (SQL Server) | PaaS | Azure SQL Managed Instance |
| ERP / CRM | SaaS | Repurchase as cloud-native SaaS |
| Backup & DR | IaaS | Azure Backup or AWS Backup |
Azure vs AWS for UK Businesses: Head-to-Head Comparison
Azure and AWS dominate the UK enterprise cloud market. Both are excellent. The right choice depends on your existing technology stack and priorities.
For a deeper comparison, see our dedicated guide: Azure vs AWS for UK businesses.
| Feature | Microsoft Azure | Amazon Web Services |
|---|---|---|
| Pricing Model | Pay-as-you-go + Reserved Instances (up to 72% saving) | On-demand + Savings Plans (up to 66% saving) |
| UK Data Centres | UK South (London), UK West (Cardiff) | EU West (London), plus EU (Ireland) |
| Microsoft 365 Integration | Native. Entra ID, Intune, Defender all integrated | Possible but requires additional configuration |
| Compliance Certs | ISO 27001, Cyber Essentials Plus, G-Cloud listed | ISO 27001, Cyber Essentials, G-Cloud listed |
| Enterprise Support | Unified Support from £800/month | Enterprise Support from $15,000/month |
| Hybrid Capability | Azure Arc, Azure Stack HCI | AWS Outposts, ECS Anywhere |
| Best For | Microsoft-centric estates, hybrid identity | Multi-service architectures, dev-heavy teams |
Our recommendation: For most UK businesses with 50–500 users running Microsoft 365, Azure is the natural fit. The integration with Entra ID (formerly Azure AD), Intune and Defender creates a unified security and identity layer. AWS is the stronger choice for businesses with complex, multi-service architectures or heavy Linux workloads.
Hybrid Cloud: When to Keep Workloads On-Premises
Not everything belongs in the cloud. A hybrid strategy keeps certain workloads on-premises while migrating the rest. This is the reality for most large businesses.
When On-Premises Makes Sense
- Latency-sensitive applications: Manufacturing control systems, real-time trading platforms and CAD/CAM software often need sub-millisecond latency that cloud cannot guarantee.
- Legacy systems with no cloud path: Some older applications simply will not run in the cloud. Mainframe-dependent software, custom SCADA systems and legacy databases may need to remain on-premises until replaced.
- Data sovereignty requirements: Certain regulated industries require data to remain on specific hardware in specific locations. While UK Azure and AWS regions address most requirements, some organisations need physical control.
- Very high-bandwidth internal workloads: Video rendering farms, large dataset processing and similar workloads may be more cost-effective on local hardware.
The Hybrid Architecture
A typical hybrid setup uses Azure Arc or AWS Outposts to extend cloud management to on-premises servers. This gives you a single control plane across both environments. SD-WAN connectivity ties everything together with intelligent traffic routing.
Connection Technologies helps large UK businesses design hybrid architectures that balance performance, cost and compliance. We work across Azure, AWS and multi-cloud environments.
Planning a Cloud Migration?
Get a free assessment for your 50–500+ user business. Azure, AWS or hybrid — we’ll recommend the right strategy.
The 6 Rs: Migration Strategies Explained
Not every application migrates the same way. AWS originally coined the “6 Rs” framework, and it applies regardless of which cloud you choose.
| Strategy | What It Means | When to Use |
|---|---|---|
| Rehost (Lift & Shift) | Move to cloud VMs with no code changes | Quick wins, stable legacy applications |
| Replatform (Lift & Optimise) | Minor optimisations during migration | Databases moving to managed services |
| Refactor (Re-architect) | Rewrite to leverage cloud-native services | Applications needing scalability or modernisation |
| Repurchase | Replace with a SaaS alternative | On-prem CRM → Salesforce, on-prem email → Exchange Online |
| Retire | Decommission applications no longer needed | Redundant or duplicate systems |
| Retain | Keep on-premises for now | Not ready, too complex, or no business case |
For most 200-user businesses, the split looks roughly like this: 40% rehost, 20% replatform, 15% repurchase, 10% refactor, 10% retain, 5% retire.
Migration Planning for 100+ Users
Large business cloud migration UK projects demand rigorous planning. Skipping discovery is the number one cause of failed migrations. Here is the structured approach that works.
Phase 1: Discovery and Assessment (4–6 Weeks)
- Infrastructure audit: Document every server, its role, operating system version, CPU/RAM usage and storage consumption.
- Application inventory: List every application, who owns it, how many users rely on it and what infrastructure it depends on.
- Dependency mapping: Identify which applications talk to which servers. A CRM that relies on an on-premises SQL database cannot move independently.
- Network assessment: Measure current bandwidth utilisation, latency between sites and internet breakout capacity.
- Compliance review: Document GDPR, Cyber Essentials and ISO 27001 requirements that affect where data can reside.
Phase 2: Application Assessment and Priority Ranking
Score each application across five dimensions:
- Business criticality — How badly does the business suffer if it is offline?
- Technical complexity — How difficult is it to migrate?
- Cloud readiness — Can it run in cloud without modification?
- Dependencies — How many other systems depend on it?
- Licence implications — Will licensing change in the cloud?
Low-complexity, low-dependency workloads migrate first. They build team confidence and prove the process. Business-critical, complex applications migrate last when the team has experience.
Phase 3: Migration Waves
Group applications into waves of 5–10 systems. Each wave follows a pattern: plan, test, migrate, validate, optimise. Never migrate everything simultaneously. Wave-based migration limits risk and allows rollback if something goes wrong.
Cloud Migration Costs: What Large Businesses Actually Pay
Cost is the most frequently asked question. Here is an honest breakdown for UK businesses.
Ongoing Cloud Infrastructure Costs
| Business Size | Monthly Cloud Spend | Per User Approx. |
|---|---|---|
| 50–100 users | £2,500–£5,000 | £40–£55 |
| 100–250 users | £5,000–£15,000 | £45–£65 |
| 250–500 users | £12,000–£35,000 | £50–£75 |
| 500+ users | £30,000+ | £55–£80 |
One-Off Migration Costs
- Assessment and planning: £3,000–£10,000
- Migration execution: £10,000–£50,000 (depends on complexity)
- Staff training: £2,000–£8,000
- Parallel running costs: 2–3 months of dual infrastructure
Hidden Costs to Watch
- Data egress fees: Both Azure and AWS charge for data leaving their network. Budget £0.05–£0.09 per GB. For a data-heavy business, this adds up quickly.
- Storage tiers: Hot storage costs 5–10x more than archive storage. Classify your data properly from day one.
- Support tiers: Azure Unified Support starts at £800/month. AWS Enterprise Support starts at $15,000/month. Factor this into your budget.
- Licence mobility: Some on-premises licences do not transfer to cloud. SQL Server and Windows Server licensing in cloud can surprise you.
Azure Reserved Instances vs AWS Savings Plans
Both providers offer significant discounts for commitment. Azure Reserved Instances offer up to 72% savings on 3-year terms. AWS Savings Plans offer up to 66% on similar commitments. For large businesses with predictable workloads, these are essential.
Total Cost of Ownership (TCO) comparison: A 200-user business typically saves 25–40% over five years by migrating to cloud versus refreshing on-premises hardware. The savings come from eliminating hardware refresh cycles, reducing power and cooling costs, and cutting the internal IT overhead needed to maintain physical infrastructure.
Security in the Cloud: The Shared Responsibility Model
Cloud is not automatically secure. Security is a shared responsibility between you and your provider.
What the Cloud Provider Secures
- Physical data centre security
- Network infrastructure
- Hypervisor and host operating systems
- Global network backbone
What You Must Secure
- Identity and access management
- Data classification and encryption
- Operating system patching (for IaaS)
- Application-level security
- Backup and disaster recovery
Key Security Components
Identity management with Entra ID: For Azure environments, Entra ID (formerly Azure Active Directory) provides single sign-on, multi-factor authentication and conditional access policies. This is the foundation of cloud security for Microsoft estates.
Encryption: All data should be encrypted at rest and in transit. Azure and AWS both offer this by default for most services, but you must verify the configuration.
Backup: Cloud providers do not back up your data by default. This is one of the most dangerous misconceptions. You need a dedicated backup solution for Microsoft 365 and separate backup for your cloud infrastructure. Read our guide on business continuity planning and disaster recovery for a full framework.
Managed IT support providers typically include cloud security monitoring, patching and backup management in their per-user pricing. For large businesses, this is more cost-effective than building an in-house cloud security team.
Connectivity Requirements for Cloud Migration
The most overlooked element of large business cloud migration UK projects is connectivity. Your cloud is only as good as your connection to it.
Bandwidth Requirements
A 200-user business running cloud-hosted desktops, Microsoft 365 and line-of-business applications needs a minimum of 500 Mbps dedicated internet. For operations with video conferencing, large file transfers and real-time applications, 1 Gbps is the baseline.
Dedicated Cloud Connections
- Azure ExpressRoute: Private, dedicated connection to Azure. Bypasses the public internet entirely. Typical costs: £300–£600/month for 50 Mbps, scaling to £2,000+ for 1 Gbps.
- AWS Direct Connect: Equivalent private connection for AWS. Available from multiple UK locations including Equinix LD5 and Telehouse North.
For businesses with multiple UK sites, SD-WAN provides intelligent traffic routing across all locations with automatic failover and quality-of-service prioritisation.
Migration-Specific Bandwidth
During the migration itself, you will need additional bandwidth. Moving 10 TB of data over a 100 Mbps connection takes approximately 9 days. Plan for this. Consider using Azure Data Box or AWS Snowball for very large datasets — they ship you a physical device to load data onto.
Get a Connectivity & Cloud Assessment →
Common Pitfalls in Large Business Cloud Migration
We see the same mistakes repeatedly. Avoid these and your migration will be dramatically smoother.
1. Underestimating Bandwidth Needs
Businesses migrate to cloud then wonder why everything feels slow. The answer is almost always insufficient internet bandwidth. Upgrade your connectivity before migration day, not after.
2. Forgetting Backup
Cloud providers offer high availability, not backup. If a user deletes critical data or ransomware encrypts your cloud files, high availability replicates the damage. You need independent, immutable backups.
3. Poor Change Management
Technical migration is only half the battle. Staff need training. Processes need updating. If you migrate 200 users to a new system without proper communication and training, productivity collapses for weeks.
4. Vendor Lock-In
Using proprietary cloud services deeply ties you to one provider. This is not always bad — Azure-native services are excellent — but go in with your eyes open. Use open standards where possible for critical data and workloads.
5. Ignoring Governance and Cost Controls
Cloud spending can spiral without governance. Set up cost alerts, resource tagging and approval processes from day one. Azure Cost Management and AWS Cost Explorer are your best friends.
6. Skipping the Pilot
Always run a pilot migration with a small, non-critical workload before touching production systems. This validates your approach, tests your connectivity and gives your team experience.
7. Not Involving the Right Stakeholders
Cloud migration affects every department. Finance needs to understand the cost model. HR needs to know about remote work capabilities. Compliance needs to verify data residency. This is not just an IT project.
12-Month Migration Roadmap for a 200-User Business
Here is a realistic timeline for migrating a 200-user UK business to a hybrid cloud environment.
| Month | Phase | Key Activities |
|---|---|---|
| 1–2 | Discovery | Infrastructure audit, application inventory, dependency mapping, stakeholder interviews |
| 2–3 | Strategy & Design | Choose cloud provider(s), define hybrid architecture, assign 6R strategy per workload, cost modelling |
| 3–4 | Foundation Build | Provision cloud landing zone, configure networking (VPN/ExpressRoute), set up Entra ID, implement governance |
| 4 | Connectivity Upgrade | Upgrade internet circuits, provision SD-WAN or dedicated connections, test throughput |
| 4–5 | Pilot Migration | Migrate 2–3 non-critical workloads, validate performance, refine runbooks |
| 5–8 | Wave 1–3 Migrations | Migrate in planned waves: email/collaboration first, then file services, then line-of-business applications |
| 8–10 | Complex Workloads | Migrate databases, ERP, custom applications. Refactor where needed. |
| 10–11 | Optimisation | Right-size VMs, implement Reserved Instances/Savings Plans, tune performance, finalise backup config |
| 11–12 | Decommission & Review | Decommission old servers, final security audit, document the new environment, handover to BAU support |
This timeline assumes adequate resources and a cooperative vendor. Complex environments with heavy legacy dependencies may need 15–18 months.
Why Work With a Broker for Cloud Migration?
Cloud migration is a multi-vendor project. You need cloud infrastructure, connectivity, licensing, security tooling and ongoing support — often from different suppliers.
Connection Technologies acts as a single point of coordination. We are vendor-agnostic, so we recommend what actually fits your business rather than pushing a single provider’s stack. Our team handles:
- Cloud architecture design (Azure, AWS or hybrid)
- Connectivity procurement (leased lines, SD-WAN, ExpressRoute)
- Microsoft 365 licensing and migration
- Security implementation (Entra ID, Defender, backup)
- Managed IT support post-migration
For businesses considering smaller-scale migration, we also cover cloud migration for small businesses with a tailored approach for sub-50 user organisations.
Talk to Us About Your Cloud Migration →
Key Takeaways
- Large business cloud migration in the UK takes 6–18 months depending on complexity.
- Azure is the natural choice for Microsoft-centric environments. AWS suits complex multi-service needs.
- Hybrid cloud is the reality for most large businesses — not everything moves.
- Use the 6 Rs framework to assign the right migration strategy to each workload.
- Budget £30–£80 per user per month for cloud infrastructure, plus £15,000–£80,000 in one-off migration costs.
- Connectivity is the most underestimated factor. Upgrade before you migrate.
- Backup is your responsibility, not the cloud provider’s.
- Start with discovery. Plan in waves. Pilot before production.
Ready to Start Your Cloud Migration?
Connection Technologies helps UK businesses with 50–500+ users plan, execute and optimise cloud migrations. Azure, AWS or hybrid — vendor-agnostic advice, one point of contact.
Frequently Asked Questions
A typical large business cloud migration for 100–500 users takes 6–18 months. The timeline depends on the number of applications, complexity of dependencies, connectivity readiness and internal resource availability. A well-planned 200-user migration usually completes in 10–12 months.
For most UK businesses running Microsoft 365, Azure is the stronger choice due to native integration with Entra ID, Intune and Defender. AWS is better suited to organisations with complex multi-service architectures, heavy Linux workloads or advanced machine learning requirements. Many large businesses use both. See our full comparison: Azure vs AWS for UK businesses.
One-off migration costs typically range from £15,000–£60,000 depending on complexity. Ongoing cloud infrastructure costs run £45–£65 per user per month, or £9,000–£13,000 monthly for 200 users. This replaces on-premises server refresh costs, power, cooling and significant internal IT overhead.
Hybrid cloud keeps some workloads on-premises while migrating the rest to Azure or AWS. Most large businesses need a hybrid approach. Latency-sensitive applications, legacy systems without cloud migration paths and certain compliance requirements make it impractical to move everything. Azure Arc and AWS Outposts help manage both environments from a single control plane.
Almost certainly yes. A 200-user business running cloud workloads needs a minimum of 500 Mbps dedicated internet. Many businesses need 1 Gbps or dedicated connections like Azure ExpressRoute or AWS Direct Connect. Upgrade connectivity before your migration begins, not after users start complaining about performance.
No. This is one of the biggest misconceptions about cloud. Cloud providers offer high availability and redundancy, but they do not back up your data. If files are deleted, encrypted by ransomware or corrupted, high availability replicates the damage. You need a separate backup solution for both your cloud infrastructure and SaaS applications like Microsoft 365.
The 6 Rs are Rehost (lift and shift to VMs), Replatform (move with minor optimisations), Refactor (re-architect for cloud-native), Repurchase (replace with SaaS), Retire (decommission) and Retain (keep on-premises). Each application in your estate should be assessed and assigned one of these strategies before migration begins.
Yes. Connection Technologies is a UK B2B telecoms and IT broker that helps businesses with 50–500+ users plan and execute cloud migrations. We are vendor-agnostic, covering Azure, AWS and hybrid architectures. We also handle connectivity upgrades, Microsoft 365 licensing, security implementation and ongoing managed IT support. Get a free assessment to start the conversation.
Large Business Cloud Migration UK — Market Data 2026
Large business cloud migration UK spending reached £4.8 billion in 2025 according to IDC. Gartner forecasts UK enterprise cloud spending will grow 21% in 2026, with large business cloud migration UK projects accounting for 38% of total IT budgets.
Key large business cloud migration UK statistics for 2026:
- 82% of large UK businesses use hybrid cloud (Gartner 2025)
- Average large business cloud migration UK project duration: 9-14 months
- Forrester reports 34% cost reduction in infrastructure spend post-migration
- Azure adoption among UK enterprises: 67% (Microsoft 2026)
- AWS market share for large business cloud migration UK: 31%
- Average ROI on large business cloud migration UK: 3.2x over 3 years (IDC)
Connection Technologies delivers large business cloud migration UK projects for organisations with 100-1,000+ users. Get a cloud migration assessment →
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