Chris Huhne's ex-wife Vicky Pryce will stand trial today over claims she took his speeding points after he dramatically admitted lying yesterday.

The former Cabinet minister and Eastleigh MP is facing jail after finally pleading guilty to lying over who was driving his car when it was clocked speeding in March 2003.

After nearly two years proclaiming his innocence and fighting to have the case dropped, Huhne changed his plea at the start of the pair's trial at Southwark Crown Court, promptly resigning as Liberal Democrat MP for Eastleigh and ending what was once a promising political career.

Respected economist Pryce, 60, has already pleaded not guilty to perverting the course of justice by taking her then-husband's points and is expected to adopt a defence of marital coercion at the start of her trial at Southwark Crown Court today.

Huhne's attempts to have the case against him thrown out can now be reported after he yesterday admitted lying, despite last week telling the court he was not guilty.

Huhne was granted unconditional bail until sentencing, but Mr Justice Sweeney warned the 58-year-old to have ''no illusions whatsoever'' about the sentence he could receive.

Perverting the course of justice carries a maximum life prison term - but the average is around 10 months.

Allegations over the point swapping arose in 2011 after Huhne left Pryce the previous year for PR adviser Carina Trimingham, ending the couple's 26-year marriage.

After pleading guilty yesterday, Huhne immediately announced he was standing down from parliament - sparking a by-election in marginal Eastleigh that could test coalition relations to the limit.

Speaking outside court, he said: ''Having taken responsibility for something that happened 10 years ago, the only proper course of action for me is to resign my Eastleigh seat in Parliament, which I will do very shortly.''

Liberal Democrat leader Nick Clegg said he was ''shocked and saddened'', but that Huhne was doing the right thing by quitting the Commons.

He also voluntarily removed himself from the Privy Council - giving up the Right Honourable title granted to senior politicians.

But there was no sign of him handing back the £17,000 severance payment he received when he quit the Cabinet to fight the charges last February.

The developments sent shockwaves through Westminster, where Huhne had been telling friends he expected to be cleared.

The MP was only narrowly beaten by Mr Clegg for the party leadership in 2007, and until his tumultuous downfall was still regarded by many as the Deputy Prime Minister's natural successor.

His exit now raises the prospect of a major coalition clash in the by-election for his seat.

Huhne had a majority of 3,800 at the 2010 general election, but Eastleigh is viewed as a key target seat for the Conservatives if they are to get an overall majority in 2015.

There is also the prospect of UK Independence Party (Ukip) leader Nigel Farage, who previously stood unsuccessfully in the seat, making another run for Parliament.

Eastleigh Borough Council's Liberal Democrat leader Keith House said he was ''very sad'' about ''hard-working MP'' Huhne's resignation.

''The Liberal Democrats have a solid base in Eastleigh. They have won every election here for eight years and we will go forward,'' he said.

The Tory candidate is likely to be business consultant Maria Hutchings, 51, who famously assailed Tony Blair over care and education for her autistic son during the 2005 general election campaign.

A local party source said: ''Maria is popular in the local party and has already been campaigning in Eastleigh.''

To see how the drama unfolded yesterday and for all the latest on the Chris Huhne saga - click here