Where is the mast, really? Lease plans, the reality on the ground and telecoms lease renewals

In brief

What happens when a telecoms mast has stood in the same spot for more than 20 years, but the lease plan puts it somewhere else? In On Tower UK Limited v AP Wireless II (UK) Limited, a landlord argued that this mismatch undermined a mast operator’s attempt to renew its leases at two rural sites. The County Court disagreed, and the operator won at both sites in a judgment handed down on 22 September 2026.

There are two key messages. First, when deciding what land a lease covers, the court will look at what the parties would have understood standing on site with the plan in hand, not at a digital overlay of the plan onto Ordnance Survey mapping. Second, a tenant’s formal request to renew (a “section 26 request”) will be read in a common-sense way: a landlord who knows what is on the ground will be taken to understand that the request covers the site the tenant actually occupies. 

The two sites

On Tower operates mast sites across the UK. AP Wireless buys up landlords’ interests in such sites, and so became On Tower’s landlord at many of them. Each site in this case was a fenced compound, no more than roughly 10m by 10m, containing a tall mast, equipment cabinets and other plant, set on a larger area of farmland or woodland.

Both leases described the site as land edged red on a plan “for identification only”. An independent surveyor matched the plans to Ordnance Survey mapping and found that neither compound sat squarely within its red box. Both sides accepted that neither compound had moved in over 20 years. The rent had always been paid and accepted on the basis that the lease covered the compound as built.

Barber’s Moor, Lancashire, concerned a compound at the far end of a farm driveway, beyond the farmhouse. The 20-year lease was granted in 1999 at an initial rent of £3,500 a year, before the compound was built. The compound had the same shape as the one on the plan but sits a little over 10 metres east of it, with only about a 10% overlap. AP Wireless took a 25-year lease of the site in 2022.

Commons Wood, East Sussex, concerned a compound in woodland on a farm at Northiam, reached by a track. The 25-year lease was granted in 2004 at an initial rent of £7,599 a year, replacing a 1996 lease. A compound already existed, and the plan showed this. The overlap with the red box was about 90%. AP Wireless bought the freehold in September 2022.

On Tower served requests to renew both leases in 2022. AP Wireless argued that the requests covered only the land in the red boxes, not the land actually occupied, and so were invalid.

What did the court decide?

On Tower won at both sites, but for different reasons.

Point 1: lease plans are a guide

The judge said a lease plan is only one piece of evidence of what land was let. The question is what the parties intended, judged by someone standing on site at the time with the plan in hand. A plan marked “for identification only” does not automatically decide the boundary: it may be the best evidence, but everything relevant has to be weighed.

At Commons Wood, this settled the matter. The plan showed the existing compound, so anyone standing in the wood in 2004 with the plan could easily have lined it up with what was in front of them. 

Barber’s Moor was harder. The compound did not exist when the lease was signed, and the plan relied on a “pole” and a tarmac path whose 1999 positions nobody could now prove. The judge could not be sure that the compound had been built where the parties originally intended. However, he decided that AP Wireless could not now go back on the position everyone had accepted for over 20 years. The landowner had watched the compound being built on its farm and said nothing. Rent had been paid and reviewed on the same basis throughout. In legal terms this is a “proprietary estoppel”; in practical terms, the leased site is the compound as built, plus a 2-metre strip around it.

Point 2: renewal requests are read with common sense

Each request described the property as the “Telecommunications Equipment” at the site, “more particularly described in the lease”. Although they did not need to decide the point, the judge said this would not have invalidated the requests. A landlord receiving the request can be taken to know what is actually on its land, namely that the operator occupies the compound and always has done under the lease. That landlord would understand the request to cover that site.

Even if there were a genuine gap between the land in the lease and the land occupied, that would be a question for the main renewal hearing, not a reason to throw out the request. A renewal request simply triggers rights the tenant already has; it does not create new ones. In practice, this makes it very difficult for a landlord to defeat a renewal at the outset by pointing to a plan mismatch.

Land occupied outside the lease

AP Wireless had also argued that, even if On Tower had spread onto land outside its lease (i.e. encroached), that extra land could not benefit from the renewal rights. The judge did not need to decide this, but he said he would have rejected the argument. Where a tenant has occupied extra land for many years without the landlord objecting, that land can come to be treated as part of the lease and protected in the same way.^[1] Landowners who turn a blind eye to an operator’s creeping occupation may find it hard to recover that land later.

Why it matters and what to do

This is a County Court decision and turns partly on its facts, but its message is clear: the courts will not let an old, imprecise lease plan undermine the renewal of a long-established site. The same approach could apply to any business lease where what is on the ground does not quite match the plan, such as a car park, a yard or a plant room.

The telecoms setting adds weight. Many mast sites are still held on leases granted before the Code was reformed in 2017, and these are renewed under the business lease renewal regime. Once renewed, operators gain the protections of the modern Code. Given the public interest in keeping mobile networks running, courts appear unlikely to favour technical arguments aimed at delaying or blocking a licensed operator’s renewal. That is especially so where, as here, the landlord knew about the discrepancy from its own surveyors’ reports when it bought in, and raised it only once the renewal was in court.

Practical tips

Landowners and investors should check early where masts and compounds actually sit compared with the lease plans, ideally at acquisition. They should also raise any discrepancy promptly, rather than continuing to accept rent and leaving the point in reserve. Operators should describe the premises in renewal requests by reference to the existing lease and the equipment on site, and keep good records of how each site has been occupied and dealt with over time. As this case shows, 20 years of consistent dealings can matter more than the lines on a plan.

Article co-authored by Ben Widdowson, Trainee Solicitor at CMS.