Sixsmith's career

1980-1997: BBC correspondent 1998: Becomes press secretary for Harriet Harman 1999: Takes communications role at GEC 2001: Joins transport department

Now there is speculation Mr Sixsmith could follow a similar fate because of reports he and controversial spin doctor Jo Moore cannot work with each other.

The former BBC correspondent had a unity message on Friday when he branded the row "complete nonsense" and said both he and Ms Moore were committed to improving public transport.

'Dirty tricks' claims

Mr Sixsmith joined the Transport Department last November, replacing Alun Evans.

Mr Evans was reportedly forced out of his job after refusing to take part in a dirty tricks campaign against London transport commissioner Bob Kiley.

The hot question is whether Sixsmith and Moore can work together

Downing Street said the appointment of Mr Evans had never been long term and Cabinet Secretary Richard Wilson said there had been no dirty tricks campaign.

But there was more controversy when Mr Sixsmith's deputy was appointed earlier this year.

Mr Sixsmith was said to have had a "blazing row" with Mr Byers, who was reportedly pushing for a friend of Ms Moore to get the job.

Instead, the post went to career civil servant Ian Jones.

Defining events

Mr Sixsmith's civil service career follows his time at the BBC, reporting from many of epoch-making events of the 1980s and 1990s.

Educated at Oxford, Harvard and the Sorbonne, he joined the BBC in 1980 and worked as a foreign correspondent in Brussels, Geneva, Warsaw and Washington.

Those years saw Mr Sixsmith reporting on the collapse of communism in the Soviet Union and Poland, eight super power summits, war in Afghanistan, the Los Angeles earthquake and Bill Clinton's first term as US president.

Married with four children, he became Ms Harman's press secretary in January 1998.

Ms Harman was sacked later that same year and Mr Sixsmith left the department himself to join GEC, one of Britain's biggest companies which subsequently became Marconi.

The company later saw its share value plummet by more than 95% and Mr Sixsmith moved again to the transport department post, said to command a �100,000 salary.