The Right To Dig Down: Issues Surrounding Basement Developments

As viable development land remains in short supply, it is unsurprising that developers are looking for ways to increase density within existing sites. While we have previously commented on the difficulties of building upwards into airspace ( see update), the recent High Court decision in Gorst v. Knight [2018] EWHC 613 (Ch) highlights some of the legal difficulties of digging down to create additional basement space below an existing building.

In Gorst v Knight the High Court held that the long lease of a maisonette did not demise the subsoil and consequently the tenant had no right to excavate the basement area to create additional living space.

The facts

The case concerned an appeal by the tenant of a ground floor and basement maisonette (Flat 1) against a ruling that the demise of their long lease (the Lease) did not extend to the subsoil beneath the premises.

The Lease defined the premises as:

"maisonette shown edged red on the plan annexed hereto and known as Flat 1... being on the ground floor of the building edged blue on the plan (the Building)... and generally including all parts of the building... in the case of a lower maisonette below the line dividing equally the joists between the ground and first floor".

There was also an interpretation provision which confirmed that "maisonette" included reference to the foundations and the void or cellar below the ground floor.

Since the cellar was only five feet high, the tenant applied for and obtained planning permission to dig into the subsoil to increase the depth by another four feet to create a useable living space. The question arose as to who had the right to the subsoil.

If the subsoil had been demised to the tenant pursuant to the Lease then the tenant would have the right to excavate subject to the landlord's consent to alter. Such consent could not be unreasonably withheld by virtue of the Landlord and Tenant Act 1927.

However, if the landlord had not demised the subsoil then the tenant would have no right to excavate and any such excavation would, in the absence of the landlord's consent, amount to a trespass. It would be possible to seek the landlord's consent for the work but such consent would not be governed by any requirement on the landlord to act reasonably and would instead be a matter of negotiation between the parties.

Observations

After considering the case law on both upward and downward development, the Court made the following observations:

there is a legal...