Accounting giant KPMG has completed its pre-let of 20 Grosvenor Street at a rent of around £125/sq ft for the whole building, setting a new benchmark in London’s West End.

The deal is just under the rent paid by Singaporean company Temasek of £130/ sq ft at Standard Life Investment’s 23 King Street, where it took 8,400 sq ft across the top two floors last September.

But the KPMG pre-let is for more than quadruple the spaceat Grosvenor’s 40,000 sq ft building, on a 15-year lease.

The last pre-let of this size in Mayfair was when Ares Management completed its deal for 30,000 sq ft at the Crown Estate and Exemplar Properties’ W1 in January at a rent of more than £100/ sq ft.

Craig McWilliam, executive director for Grosvenor’s London estate, said: “This pre-let to KPMG, nine months before the development completes, is a testament to both the building and to Mayfair as a place businesses chose to locate.”

The West End office will be for a “client hub” for KPMG. It is currently split between two office buildings in London: 15 Canada Square in Canary Wharf and 8 Salisbury Square in the City.

But it agreed a deal in August to replace its Salisbury Square office from 2015 with a further 200,000 sq ft in Canary Wharf at 30 North Colonnade due to a lease expiry.

Simon Collins, UK chairman at KPMG, which has appointed Russell Sage Studio to help design the new space, said: “Opening a building in the heart of Mayfair for our clients is exciting and our ambition is to create a very different meeting space.”

Knight Frank and Savills advised Grosvenor; DTZ advised KPMG.