What a Leased Line Costs in London: 12 Real Address Quotes
We ran live carrier quotes at twelve London and Thames Valley business addresses. Here is what a leased line actually costs, how long it takes to install, and the £10 upgrade most buyers miss.
Nerdster Team
Ask what a leased line costs and you will be told “it depends on your address”, which is true and useless. So we went and got the numbers.
In early September 2026 we ran live carrier quotes at twelve business addresses across London and the Thames Valley, through the same system that powers our price check. Each address was priced by more than ten UK carriers. Each quote came back with between 131 and 233 individual products. What follows is what those quotes actually said.
Two things before the numbers. These are our prices, not a market survey: they are what we would sell the line for, on a 36-month term, excluding VAT. And they were true on the day. Carrier pricing moves, and the only figure that matters for your building is a fresh quote at your own postcode.
What a leased line costs
| Address | 1 Gb symmetric | 100 Mb symmetric | Install lead time |
|---|---|---|---|
| City of London, EC2R | £280 | £190 | 45 working days |
| City, EC3A | £280 | £190 | 45 working days |
| Aldgate, E1 | £280 | £190 | 45 working days |
| Mayfair, W1K | £280 | £190 | 45 working days |
| Covent Garden, WC2H | £280 | £190 | 45 working days |
| Bloomsbury, WC1N | £280 | £190 | 45 working days |
| Westminster, SW1A | £280 | £190 | 45 working days |
| Islington, N1 | £280 | £190 | 45 working days |
| Camden, NW1 | £280 | £190 | 45 working days |
| Hampstead, NW3 | £280 | £190 | 45 working days |
| Egham, TW20 | £315 | £260 | 46 working days |
| Reading, RG1 | £315 | £225 | 55 working days |
Per month, ex VAT, 36-month term, no install charge at any of these addresses.
The first thing that jumps out is how flat central London is. Ten addresses spread from Aldgate to Hampstead, across postcodes with wildly different rents, and the gigabit price is identical at every one. Your address changes whether a carrier can reach you and how long it takes them. Within a city this well served, it barely changes what you pay.
The second is that the Thames Valley is not London. Egham and Reading both came back £35 a month higher for the gigabit, and Egham was £70 a month higher for 100 Mb than the same product in the City. Over a three-year term that is £2,520 more for the same service. If you are choosing between offices, connectivity is a real line in the comparison.
The £10 upgrade almost nobody is offered
Here is the finding worth the most money to the most people.
At eleven of the twelve addresses, moving from a 500 Mb leased line to a 1 Gb leased line cost £10 a month more. Not £100. Ten pounds, for double the speed.
This is not a discount and it is not a trick. When a carrier builds a leased line they install a bearer, and on almost every modern build that bearer is capable of a gigabit. The speed you are sold on it is a configuration, not a physical constraint. Once the fibre is in the ground, the difference between selling you 500 Mb and 1 Gb is a number in a provisioning system.
Which means that if you have been quoted 500 Mb, you should ask what the gigabit costs before you sign anything. On these numbers there is a good chance the answer makes the 500 Mb quote look silly. The same logic runs up the ladder: check the next speed tier every time, because the pricing curve is not smooth.
Most of what a carrier offers you is not worth buying
Across the twelve addresses, carriers returned a median of 177 products each. After pricing them and removing the ones that made no sense, a median of nine remained worth showing at a 36-month term.
That is not us being fussy. Roughly four in every ten priced options were worse value than another option at the same address — slower for the same money, or the same speed for more money, or a term that cost more and delivered less. They exist because carriers publish a full matrix of speeds and terms, not because anyone should buy them.
This is the part of the market that a “from £X” price on a comparison site hides completely. You are shown a headline number, you enquire, and somebody sells you whatever is in front of them. The work is not finding a price. The work is throwing away the 168 products that are wrong for you.
Nine weeks, and nobody tells you
Every London address came back at 45 working days for a gigabit leased line. Egham was 46. Reading was 55.
Forty-five working days is nine weeks. Not one of the comparison sites or carrier landing pages we looked at while building this states a lead time before you hand over your details, and it is the single most disruptive fact about buying a leased line. If your lease starts in six weeks, no amount of urgency changes physics: an engineer has to build fibre into your building.
Two things follow from that. Order earlier than feels necessary, because the clock starts when the order is placed, not when you decide. And if you are moving into a space before the fibre lands, a 4G or 5G line can be live in about a week and will keep you trading in the gap. Where the exchange serving your building is not already connected, expect 60 to 90 working days rather than 45.
Where full fibre is the right answer
The cheapest full-fibre line at these addresses started around £35 a month, against £280 for a gigabit leased line. That is an eight-fold difference, and for a lot of businesses full fibre is the correct decision.
What the extra buys you is not headline speed. It is:
- The same speed in both directions. Full fibre downloads fast and uploads at a fraction of that. If you run a phone system, video calls, or push large files out, upload is what you actually feel.
- No contention. A leased line is yours. Full fibre shares capacity with the neighbourhood, which is why it slows down at four o’clock.
- A commitment you can hold someone to. Dedicated fibre carries 99.9% availability, a six-hour repair target around the clock and service credits when either is missed. Full fibre carries a 24 to 48 hour target and no credits.
The honest test is what a day offline costs you. If the answer is “we would lose some work”, full fibre with a 4G backup is usually the better spend. If the answer is “we would stop trading”, you are buying the service level, and the leased line is the cheap option.
How to use this
Take the table as a sanity check, not a quote. If someone has offered you a gigabit in central London at £500 a month, you now know what that should look like. If you are being sold 500 Mb, ask about the gigabit. If nobody has told you a lead time, ask before you sign, and get it in writing.
Then get a real number for your own building. Our connectivity price check runs the same live quote this article is built from, at your postcode, in about a minute, and shows the install lead time and the service level on every line. It does not ask for your details to show you prices.
Method. Twelve business addresses quoted live through our carrier platform on 3 and 4 September 2026, filtered to Fibre Ethernet, FTTP, SoGEA, broadband and cellular products. Prices shown are Nerdster’s retail prices on a 36-month term, ex VAT, and were correct on the date of the quote. Six further addresses were attempted: three returned no matching premises and three returned a carrier error. Lead times are the carrier’s own estimate for that address and remain subject to survey.
