In pictures: Broadcasting House at 75

Staff at Broadcasting House could use artificially-ventilated toilets, supposedly the first time any office in London had such luxury.

The cost of the building was about £500,000 at the time, or £25 million at today's prices.

According to the BBC's 1933 yearbook, there were 800 doors, or one for every employee.

One office - Room 101 - was said to have been the inspiration for George Orwell's book 1984.