refreshing

These are legacy buttons on the modern studio desks.
Up until the mid 90s, drinks for guests were readily available. Studios in Broadcasting House had a bell-pull system for calling a commissionaire to bring refreshments to studio guests and operators. Because there was a strict rule of silence in the control room of the studio, there were 4 bells available: coffee, tea, milk and hot water. Pulling a combination of the hand carved mahogany toggles would trigger corresponding lights in the 'Commissionaire Control Centre' and the desired drinks would be delivered.
When John Birt became Director General in 1992, Commissionaires were made redundant and coffee and tea was only available in the Council Chamber on the first floor of Broadcasting House. It was only a matter of months before biscuits were also banned.
These cuts saved a total of £10,000 in the first year. The savings were re-invested in advertising for a private catering company to supply tea and coffee to managers at high level meetings.
Modern desks in the studios are designed with digital switches replacing the mahogany bell-pulls. If Tony Hall decides to re-instate the old system, the infrastructure is already in place at no extra cost to the licence fee payer.