UK businesses are more reliant on internet connectivity than ever before. Whether it’s powering VoIP systems or simply facilitating remote working, uptime matters, and for companies that can’t afford disruption, leased line redundancy UK solutions (such as dual fibre installations) offer unmatched reliability.
Join us as we explore why a well-placed leased line for business is a wise investment, how dual lines work, and which UK providers offer the most robust redundancy setups.
What Is Leased Line Redundancy?
Leased line redundancy involves setting up a second (backup) leased line, separate from your primary connection. This ensures that the second line automatically takes over if your main fibre line is cut, fails, or suffers degradation.
Redundancy can be any of the following:
- Physical: Two separate fibre paths (from different routes or exchanges)
- Logical: Same line, but backed by a 4G/5G or broadband circuit
- Geographical: Connections from different providers or data centres
The goal: ensure your business remains online even during unexpected outages.
Why Redundancy Is Crucial in 2025
- Increased cloud dependence: Downtime impacts access to CRMs, ERPs, and collaboration tools
- VoIP and UCaaS reliance: Missed or dropped calls damage reputation and service
- Security and surveillance systems: IP cameras and alarms need constant connectivity
- eCommerce and EPOS systems: A failed connection can halt transactions
Types of Backup Leased Line Setups
Redundancy Type | Description | Best For |
Active-Passive | Backup only activates when the main fails | Most SMEs |
Active-Active | Load balancing between both lines continuously | Enterprises or high-traffic sites |
Diverse Routing | Each line runs via a completely different route | Mission-critical operations |
Dual Provider | Two leased lines from separate ISPs | Risk-averse, regulated industries |
Leased Line Redundancy vs 4G/5G Failover
Feature | Dual Leased Line | 4G/5G Failover |
Speed & Bandwidth | 100Mbps – 10Gbps | 10Mbps – 300Mbps |
Contention | 1:1 (uncontended) | Shared |
Uptime Guarantee | 99.99%+ on both lines | No SLA |
Suitable For | All operations including VoIP | Light backup traffic only |
Cost | Higher | Lower |
our verdict? If uptime is mission-critical, dual leased lines offer maximum protection and zero compromise on performance.
Which Businesses Benefit Most from Dual Leased Lines?
- Financial institutions requiring FCA/GDPR uptime guarantees
- Healthcare providers need real-time access to records.
- Call centres and customer service hubs
- eCommerce sites processing high volumes of transactions
- Businesses with contractual SLAs tied to availability
Top UK Providers Offering Leased Line Redundancy
| Provider | Redundancy options | Dual carrier Support? | From |
| Diverse routing, dual links | Yes | £399 + redundancy |
| Dual-site connectivity | Yes | £400 + |
| Separate routes, SD-WAN | Yes | £450 + |
| Active-passive options | Limited | £300 + |
| Multi-site and resilient WAN | Yes | £375 + |
Implementation Tips
- Ensure path diversity: Ask your provider to confirm that both leased lines use different ducts and exchanges
- Use separate providers: For genuine redundancy, choose different ISPs with independent infrastructure.
- Enable automatic failover: Use routers or firewalls that support dual WAN failover.
- Test regularly: Simulate failover scenarios to confirm switchover works as intended
- Use static IPs and DNS failover: Ensure smooth transition without service interruption.
Real-World Scenarios
- Retail chain: One store lost internet due to a street-level cable cut. Dual fibre kept tills, card machines, and security systems running with zero downtime.
- SaaS firm: Combined leased line + leased line redundancy with load balancing. Maintained 100% uptime across two UK offices for over 18 months.
Conclusion About Leased Line Redundancy
Internet uptime is directly tied to productivity, service delivery, and profitability. A single leased line performs exceptionally, but even the best systems can fail.
That’s why we think that investing in line redundancy UK strategies, like diverse routing or dual-provider setups, is not just insurance, it’s thoughtful planning.
