How speeding scandal put the brakes on Chris Huhne - the ruthless political operator who could have led his party into power

Relentless ambition took him close to the very top of politics – and his disgrace has left friends in shock

Huhne, circled, at a protest at Oxford in 1973

“There will be some good news soon,” Chris Huhne has repeatedly reassured political colleagues in recent months – Nick Clegg among them. The word throughout Lib Dem land was that the former Cabinet minister, one of the party’s few genuine big hitters, would soon be back in the game because his trial on a charge of perverting the course of justice would collapse.

Mr Huhne’s confidence made yesterday’s shockwaves from his decision to change his plea to guilty all the greater in Westminster. It certainly came as a bolt from the blue to Mr Clegg when Mr Huhne phoned him at his Putney home on Sunday evening to say he was going to admit the offence and resign as the MP for Eastleigh.

Mr Huhne’s reputation will now be scarred not only by the admission of a serious offence but by the gruesome text exchanges with his son which have now emerged from proceedings at Southwark Crown Court. When Mr Huhne told his 18-year-old son Peter: “Happy Christmas. Love you. Dad,” his son replied: “Well I hate you, so f*** off.” When he told Peter: “I’m proud and I love you,” the reply was: “Leave me alone, you have no place in my life and no right to be proud. It’s irritating that you don’t seem to take the point. You are such an autistic piece of s***. Don’t contact me again you make me feel sick.”

His son threatened at one point to go to the police himself if Huhne did not “accept responsibility” for the speeding offence.

For some in the Lib Dem family, this personal tragedy is almost unbearable because they are friends with Mr Huhne, his former wife Vicky Pryce and their children. Today, several were literally too upset to talk about the saga. Mr Huhne’s downfall started with his decision to leave his ex-wife when the press revealed his affair with Carina Trimingham, his former media adviser, who was previously in a civil partnership and who has been vilified by some newspapers. She told The Independent on Sunday recently: “I’m just a regular person who happened to fall in love with someone who was an MP.”

Even Mr Huhne’s friends would not deny his ambition. His enemies say it came with more than a touch of icy cold ruthlessness, an eye for the main chance and a killer instinct.

This ruthlessness extended to the end of his marriage. As his wife watched a World Cup match at their Clapham townhouse, Huhne took the call from the News of the World in another room to learn that he was about to be exposed as a cheating husband. According to his wife, a shaken Mr Huhne informed her of the affair when she emerged for some food at half-time. He told his wife, the mother of this three children, that he had 30 minutes to kill the story – so he retired to his study, decided to leave her, and scribbled down a few words to stave off the inevitable media clamour. “I am in a serious relationship with [press secretary] Carina Trimingham and I am separating from my wife,” he wrote. Then he went to the gym.

Now Mr Huhne’s political career is also suddenly over, at the age of 58. Although the allegation that his former wife took penalty points for him would have left some damage even if he had been cleared, he would probably have returned to the Cabinet before the 2015 election. He could even have climbed to the top of the party ladder.

Vince Cable, the Business Secretary, is seen as the man most likely to take over if Mr Clegg decides to stand down before the next election – a subject of speculation amongst Lib Dem activists and MPs even though Mr Clegg dismisses it. But if Mr Huhne, 11 years Mr Cable’s junior, had been acquitted, he would have been a very strong contender. “He has always networked hard to win friends and allies,” said one party insider. “Vince is a bit of a lone wolf.”

Huhne’s ruthlessness and ambition was evident five years ago when he battled it out for the party leadership with Mr Clegg. A briefing by the Huhne campaign described his rival as “Calamity Clegg”. Mr Huhne denied knowledge of it but the damage to Mr Clegg was done. Although Mr Clegg won by 511 votes, about 1,300 postal votes arrived too late and, with a late swing already in his favour, Mr Huhne might well have won if they had been allowed to count. Despite this second setback (Mr Huhne had also been beaten to the leadership by Sir Menzies Campbell in 2006) he knuckled down to work under Mr Clegg. Although not blood brothers, they have been friends for 20 years having served together as MEPs, and Mr Huhne attended Mr Clegg’s wedding.

Speculation that the Deputy Prime Minister will secretly be pleased that a potential king over the water has drowned is wide of the mark, his aides insist. Not enough “big beasts” roam in Lib Dem land. Mr Clegg needs all he can muster as he tries to drag his party from one of protest to being seen as a credible power-sharer.

Conservatives will not shed many tears at Mr Huhne’s demise – or the prospect of a winnable by-election, the first contest between coalition partners in modern times, that might just transform David Cameron’s standing in his own party when many MPs doubt he can lead them to victory in the general election in 2015.

Mr Huhne’s confrontational style round the Cabinet table did not go down well with the Tories. Prophetically, the former journalist and economist said in 2010 that the Government should not be “lashed to the mast” of its spending cuts if the medicine was not working, and acknowledged the prospect of the double-dip recession that duly arrived. He accused the Tories of resorting to “Goebbels-style” personal attacks on Mr Clegg during the referendum campaign on the alternative vote. He also branded Mr Cameron “Billy no mates” when the Prime Minister vetoed an EU fiscal pact. And when Cabinet table criticism quickly made it into the public domain, it was seen by Tories as an attempt by Mr Huhne to position himself as an alternative to Mr Clegg.

That is not how Mr Clegg viewed it. Although some of the attacks on the Tories were freelance operations by Mr Huhne, others were cleared in advance with the Lib Dem leader. “He was the hard cop, to Nick Clegg’s soft cop,” one Huhne ally said yesterday. Such different styles are useful in a coalition.

As Energy and Climate Change Secretary, Mr Huhne clashed with George Osborne, who sought to dilute the Government’s green commitments. After one Cabinet outburst, the Chancellor told Mr Huhne he was not prepared to be treated by a fellow minister acting as if he was “Jeremy Paxman on Newsnight”.

After a successful career as a business and economics journalist on papers including The Independent, Mr Huhne started a City ratings agency in 1994 in an office comprising only himself and a phone. He built up a business that made him a millionaire with several homes. The same drive and determination is still there today, but will eventually have to be channelled into something outside politics.