Margaret Thatcher's resignation, Geoffrey Howe's demotion and the Brighton IRA bomb - ministerial drivers were the silent witnesses at all these major events.

For many years, one group of people has had access to the most intimate secrets in government.

They have been invited into ministers' families and private offices, uniquely seeing both their public and private faces.

In the process, they have literally found themselves sitting in the front seat while history is made.

Ministerial car driver Denis Oliver had just started driving Margaret Thatcher when the IRA bombed the Grand Hotel in Brighton in 1984....