Robert Jackson had been involved in Tory party politics for many years

The MP for Wantage in Oxfordshire is pro-European and has spoken out in favour of the EU constitution, arguing it would strengthen the UK's ties with the continent.

He was on the liberal wing of the party and one of the few Tories who supported the reduction in the age of consent for gay men.

He has been treasurer of the Conservative Mainstream association - whose members include Europhiles Lord Heseltine and Kenneth Clarke - and supported proportional representation for European and devolved assemblies.

I have said right from the start I am a small cog in the wheel of politics...I don't have a place in the history books Robert Jackson

The 58-year-old is due to stand down at the next election.

But a recent newspaper article noted with foresight that "he is barely a Tory anymore - it is no surprise he is leaving the Commons".

Nevertheless, before he decided to defect to Labour he had a long association with the Conservative Party.

Education brief

As far back as the Heath government of the early 1970s he served as a political advisor to the late Lord Whitelaw, who was first chief whip and then Northern Ireland Secretary during the height of the troubles.

He was first elected as a Conservative MEP in 1979 - a position his wife Caroline now holds and intends to retain, despite her husband's defection.

Mr Jackson was born in Rhodesia - now Zimbabwe - and in 1980 was appointed as special adviser to the late Lord Soames, who as transitional governor of the country was overseeing its progress towards legal independence.

Robert Jackson blamed Andrew Gilligan for Dr David Kelly's death

Mr Jackson won the seat of Wantage in Baroness Thatcher's 1983 landslide general election victory.

Four years later he left the Commons back benches and became higher education minister.

But his position was marked by clashes, many of them public, with university academics over the Conservative government's attempts to reform higher education funding.

In 1990, Mr Jackson was demoted and held some lower profile positions before returning to the back benches three years later during the Major government.

Not entirely muted

He decided to stand down as an MP in November 2001, after Kenneth Clarke lost out in his bid to become leader of the Conservative Party to the Eurosceptic Iain Duncan Smith.

When he announced his defection Mr Jackson said: "I have said right from the start I am a small cog in the wheel of politics.

"I don't have a place in the history books. I might get a footnote in the history of university funding."

However, his final years in the Commons have not been entirely muted.

In 2003, he was the only Conservative MP to support Prime Minister Tony Blair's battle to increase higher education tuition fees.

And during the row between the BBC and Downing Street following the death of the weapons expert Dr David Kelly, Mr Jackson blamed the death of his constituent on the BBC reporter Andrew Gilligan.

Dr Kelly killed himself after being named as Mr Gilligan's source for a BBC news story in 2003.

It said the government had "sexed up" its Iraq dossier in the run-up to the US-led invasion to overthrow President Saddam Hussein; the Hutton report later said the allegation was "unfounded".