Beginning in 1938, the east side of the site was redeveloped with the building now housing the Ministry of Defence (MOD), now known as MOD Main Building. An undercroft from Wolsey's Great Chamber, now known as Henry VIII's Wine Cellar, a fine example of a Tudor brick-vaulted roof some long and wide, was found to interfere not just with the plan for the new building but also with the proposed route for Horse Guards Avenue. Following a request from Queen Mary in 1938 and a promise in Parliament, provision was made for the preservation of the cellar. Accordingly, it was encased in steel and concrete and relocated nine feet to the west and nearly deeper in 1949, when building was resumed at the site after the Second World War. This was carried out without any significant damage to the structure and it now rests within the basement of the building.