Former Liberal Democrat leader Sir Menzies Campbell has criticised Business Secretary Vince Cable and his allies for undermining the Coalition.
Sir Menzies warned Mr Cable, a former Labour party adviser, that exchanging text messages with opposition leader Ed Miliband would aggravate already disgruntled Tory backbenchers.
The veteran Lib Dem also dismissed suggestions by former party Treasury spokesman Lord Oakeshott, a key supporter of Mr Cable, that Nick Clegg should be replaced as leader.
In an interview with The House magazine, the former Olympian also described himself as once being the "fastest white man on earth" and told how he beat disgraced former American football star OJ Simpson in a 100m race.
Asked about Mr Cable's text messaging, Sir Menzies said: "Well, I've thought quite long and hard about this. The truth is that the thrust of this coalition, and I'm choosing my words with some care, depends upon it being...the success of this coalition depends upon everyone who participates in it being a full subscriber, and I don't think, we were using the expression pick and mix a little while ago, I don't think it helps a partnership to suggest that you may already be looking for another partner.
"If you were a Tory backbencher hearing of these things, especially one who's disaffected, who wishes there was an unrestricted Tory government, what would you make of it? Would you be encouraged to be yet more loyal to the front bench or would you say well, that's a kind of, maybe, not a green light but an amber light. Proceed with caution. An amber light to people like myself to say well, if so and so looks as if he's talking to the other lot why are we are bothering with this lot?"
He added: "People signed up for this (the coalition) and when you sign up then you've got to understand...that this was going to be a rocky road. (The Lib Dems must) get the brand right, (but) keep the same advertising agency."
Sir Ming held the British 100m record from 1967 to 1974 and ran the 200m for the GB team at the 1964 Tokyo Olympics. He said: "There was a little wrinkle, at one stage I was the fastest white man on earth...my wife gave me that title in less politically correct times. In order to do that I won a race in Mount San Antonio in Southern California, I beat a very promising up and coming young black athlete who later decided to play American football rather than be a track athlete...and his name was OJ Simpson."
Sir Ming also revealed he is considering standing down at the 2015 general election. "I haven't made up my mind and that's genuinely the case," he said. "I'm 71. I still have most of my own teeth. It's ten years since I had cancer but I'm still here. I've got a lot on my plate. I'm still apparently capable of doing it, indeed I'm still significant enough that I've become the cover story of the House magazine. I've promised my constituency association I'd make up my mind about half way through the parliament."
Mr Cable's aides dismissed the criticism of the text exchanges between the Business Secretary and the Labour leader. "Vince is not looking for a new partner. He is clearly happy in his job and is delighted with his new team and the big hitters in the department. He is committed to the Coalition Agreement."