A piece of land below a mansion block of flats in central London has sold at auction for £150,000.

The land, in Bloomsbury, has potential for excavation to become a basement.

If work goes ahead, just how delighted this would make the flat dwellers in the nine storeys above is not clear.

While the freeholder has given permission, there is no planning consent for the 2,000 sq ft space – and objections are highly (if that’s the right word) likely.

Underground extensions have become controversial in London, with complaints that work drags on for months.

Some such subterranean developments can be very extensive, involving more than one floor – meaning that the 2,000 sq ft could double or even treble – and huge engineering works.

It is thought to be the first time that an unexcavated piece of ground below a residential building has ever been sold.

Chris Coleman-Smith, head of auctions at Savills, said he has never sold such a lot before.