Nick Clegg says his father has not paid back any of his pensioner benefits, even though he does not really need them.
The deputy prime minister acknowledged that his father Nicholas, a wealthy former banker, is a "good example" of someone who the Lib Dems believe should not be entitled to benefits such as free bus passes or winter fuel allowance.
Pressed during his weekly radio phone-in on LBC 97.3 by presenter Nick Ferrari, he said that Clegg senior had not returned any of the money. "He hasn't given it back," he said.
Asked whether he would urge him to do so, he replied: "It's incredibly unfair on my dad to start dragging my dad into this show.
"My dad had a well-paid career and he and I think many other people said 'Well, hang on, I don't necessarily need this'."
Work and Pensions Secretary Iain Duncan Smith recently suggested well-off pensioners could return their benefits while the Libs Dems have said they would means-test such benefits in future.
Clegg said they were still working out at what point pensioners would be unable to claim them.
"I think what the political parties will need to do, since we are not going to change this during this parliament, is in their next manifestos in a couple of years' time, be really clear about what they say about all this," he said.
"We in the Liberal Democrats, of course, are doing work right now to work out exactly where you'd have a fair cut-off point."
Business Secretary Vince Cable, who turns 70 on May 9, confirmed he has given his winter fuel payment to Spear, a charity in his Twickenham constituency which supports homeless people.
Cable told a web-chat with parents' internet site Mumsnet: "It's my 70th birthday next week so I won't be getting a free TV licence for a while.
"I think it would be too complicated to introduce means testing for these relatively small benefits. It would be much more sensible to ensure wealthy pensioners pay tax on any benefits they receive like people in work."