For a single-site business, a fast fibre connection is usually enough. As soon as you add a second office, a warehouse, a remote team that needs to reach the same systems, or a head office that needs to talk to a manufacturing site across town, the requirements change. The connection between sites becomes part of the infrastructure, not an afterthought. That is what a wide area network, or WAN, is for. And for most North West SMEs running more than one location, the leased line is what makes it work.
This is a practical guide to leased lines and WAN connectivity for businesses with more than one site, or one site that has outgrown standard broadband.
What a leased line actually is
A leased line is a dedicated fibre connection between your premises and the provider’s network. Unlike broadband, the line is not shared with anyone else. The advertised speed is the speed you get, in both directions, at any time of day. Symmetrical upload and download. No contention with other users in the area.
Typical specifications you will see quoted:
- Speeds from 100Mbps up to 10Gbps, symmetrical
- Service level agreements covering uptime, fix times, and throughput
- Static IP addresses included
- Defined repair window, often four to six hours for a target fix
That last point is the one that matters most for businesses running anything critical. With consumer or business broadband, a fault is a queue and a best-effort engineer visit. With a leased line, the contract specifies how long the provider has to fix it, and what happens if they miss the target.
When a leased line is worth it
Leased lines cost more than broadband. The question is whether your business needs what they provide. The answer is usually yes if any of these apply:
- The business relies on cloud applications and a connection failure stops people working
- Hosted phones are in use and call quality matters
- Multiple sites need to share systems or talk to a head office
- Staff regularly upload large files (CAD drawings, video, technical data)
- Customer-facing systems are hosted on site, or remote workers connect to systems on site
- The current broadband suffers from contention, particularly at peak times
For a 30-person office running on Microsoft 365, hosted phones, and one or two cloud-hosted line-of-business applications, a leased line is usually the right answer. The increase in productivity from not losing half a day a month to connection problems pays for the upgrade quickly.
What a WAN actually means in practice
A wide area network connects your sites together so they behave as one network rather than several separate ones. Staff at the Liverpool office reach the same file servers, the same applications, and the same phone system as staff at the head office, with no difference in experience.
There are three common ways to build a WAN in 2026.
Site-to-site VPN
Encrypted tunnels run over each site’s internet connection. Cheapest to set up, since you only need internet at each site. The downside is that performance depends on the underlying internet connections. If one site has flaky broadband, the WAN will feel flaky at that site.
MPLS
A private network run by the provider, separate from the public internet. Predictable performance, prioritised traffic, and easier to manage at scale. The classic choice for businesses that need guaranteed quality between sites. Costs more per site than VPN.
SD-WAN
The current mainstream option. Software-defined networking sits on top of multiple connection types (leased line, fibre broadband, 4G or 5G failover) and decides in real time which traffic goes where. Voice and video go down the leased line. Bulk file transfers can use the backup connection. If the primary link drops, traffic switches over automatically.
For most multi-site SMEs, SD-WAN on leased lines with a secondary fibre or 4G failover at each site is the practical answer. You get the predictable performance of leased lines plus the resilience of automatic failover.
Failover and resilience
A leased line is a single point of failure if you do not plan for the line itself going down. Causes include damage from roadworks, exchange faults, and (occasionally) a digger through a duct. None of these are common, but all of them happen.
Failover options worth considering:
- A second leased line from a different carrier, on a different physical route into the building
- A fibre broadband connection as backup, automatically taking over if the leased line drops
- A 4G or 5G connection as last resort, particularly for keeping the phones working during a longer outage
The right answer depends on what stops working when the connection drops. If a four-hour outage costs the business meaningful money, dual carriers are worth the conversation. If a few hours of degraded service is tolerable, a 4G failover may be enough.
The 2027 PSTN switch-off and what it means
The traditional copper phone network is being switched off across the UK. The original deadline was the end of 2025, now revised to January 2027 by Openreach for full PSTN withdrawal. Anything that runs on a copper line — that is, ISDN, alarm lines, lift phones, and traditional phone systems — needs to move to IP before the switch-off.
For most businesses, that means hosted phones running over the same connection that handles everything else. Which is another reason the underlying connection needs to be a leased line rather than contended broadband. Voice traffic is unforgiving of jitter and packet loss, both of which are far more likely on a shared connection.
How to evaluate a leased line quote
Three questions to ask any provider.
What is the install lead time? Leased line installs typically take 60 to 90 working days where new fibre needs to be pulled, and can extend to six months in some cases. If the answer is “two weeks”, they are probably quoting an Ethernet-over-FTTC product, which is a different thing from a true leased line.
What does the SLA actually guarantee? Uptime percentage on its own is not much use. Ask for the target fix time, the service credits if they miss it, and what counts as planned maintenance versus a fault.
Is the price for the line, or for everything? Many quotes are for the access circuit only. Routing, managed firewall, IP addresses, support, and the connection from the carrier’s network to the internet may all be extra. Get a full monthly figure that covers everything you actually need.
About Blowfish Technology
Blowfish Technology is a managed IT, cloud, cyber security and connectivity provider for North West UK SMEs, with offices in Ormskirk and Liverpool. We have been trading since 1999 and hold ISO 9001, ISO 27001 and Cyber Essentials Plus.
We supply leased lines, fibre broadband, hosted phones and multi-site WAN connectivity as part of managed service agreements, which means we are accountable for the connection working, not just for arranging it. If you are running a multi-site business and your connectivity is not pulling its weight, get in touch and we will run through your options.
Connectivity that does its job
Multi-site WAN, leased lines, hosted phones and the resilience to keep them all running. Talk to us about what your business actually needs.
The Blowfish Technology team. Managed IT, cloud services, software development and connectivity for North West businesses since 1999.