The heritage watchdog will start to transfer staff to Holborn's Waterhouse Square from June, it was announced this morning.
The move will bring an end to an era which has seen EH staffers use the Savile Row building as a base from which to dictate much of the country's planning policy.
It is understood that landlord Legal & General is set to redevelop to site for other uses. EH has agreed terms to vacate the site by the middle of the year, despite the lease not running out until 2010.
London region EH staff will move straight to the new location. Some staff from 23 Savile Row will have to relocate to Swindon and 3 Bunhill Row, London EC1.
The Grade II*-listed Waterhouse Square was designed Alfred Waterhouse, the architect of London's Natural History Museum in South Kensington and Manchester Town Hall.
According to EH, the new building is part of the former Prudential Assurance building, 'boldly detailed and elaborately decorated in red brick' in the Gothic Revival style.
Rumours first emerged in late 2003 that Legal & General intended to redevelop the site with Stanhope, using designs by Eric Parry.