A 1m sq ft requirement could be triggered if the government chooses the fastest and cheapest method of restoring the Palace of Westminster.
The lease length would need to be at least six years, which is the estimated minimum time the work would take.
The Independent Options Appraisal of methods for restoring the building, published by a consortium led by Deloitte Real Estate this week, estimates that removing all MPs and staff during the works would cost £3.5bn, as opposed to carrying out a rolling programme of renovation with staff in situ, which would cost as much as £5.7bn and take up to 32 years.
The report identifies the “inability to secure adequate decant accommodation” as the greatest risk of full vacation.
The report’s findings will be considered by MPs before a course of action is decided.
