A small team in Millbank is at the heart of parliamentary broadcasting
The idea of broadcasting the proceedings of Parliament was first suggested by the BBC in the 1920s but permission was refused.
Pressure for proceedings to be broadcast grew in the 1960s and led to two experimental periods in 1968 and 1975.
Permanent radio coverage was eventually granted in 1978 although cameras were still not allowed into the House on a permanent basis.
In November 1984, cameras were installed in the Lords on an experimental basis and have remained ever since.
Resistance in the Commons continued until a close vote in 1988 when cameras were allowed into the lower Chamber, also for a trial period.
The experiment began in November 1989 for a period of 18 months and permanent access was granted in 1990.
Tight rules apply to the use of footage of parliamentary proceedings and filming in other parts of the Palace is very strictly controlled.