The Crown Estate has sold a 125-year lease on the former Public Record Office to King's College, London, and is to appoint an architect to upgrade it.
The building, designed in 1851 by Sir James Pennethorne, will be turned into a library and rare-book collection with 1250 reader places. The total cost of the lease and refurbishment will be around £20 million.
Work will involve minor structural changes to the Grade II* Victorian Gothic building in Chancery Lane. It will also include entrance designs and heating, wiring and other services.