Nick Clegg is often ambushed by unexpected callers on his LBC Call Clegg show, including once by Boris from Islington, but one caller on Wednesday, Cathy from Dulwich, had some particularly difficult things to ask him.
To the surprise of both Clegg and host Nick Ferrari, Channel 4 presenter Cathy Newman appeared on the line to quiz him about the resignation of Lord Rennard, who Clegg said had left his position on health grounds, not because of the alleged sexual impropriety.
"At the weekend you said he quit on health grounds, but now you appear to be accepting that his behaviour was part of the reason he went," she asked.
Clegg appeared startled, saying: "Channel 4, LBC, God, my head is spinning with the number of media outlets involved now.
"I have answered this question Cathy, which is that he retired on health grounds, but the allegations of his inappropriate behaviour were in the background, of course they were."
Dubbed "a self-appointed detective" by Clegg, and like many sleuths before like Sherlock Holmes or Sarah Lund, Channel 4's Cathy Newman has followed every twist and turn of the Lord Rennard scandal, producing facts to dispute almost every Lib Dem statement since the news broke.
In a detailed blog from Channel 4, Newman answered various critics including the Guardian's Michael White, who accused the channel of running "a story that has been lying around for years" on the eve of the Eastleigh by-election.
Newman said she had know about the story for three years, but had no-one prepared to go on the record with the allegations, until she was approached by Alison Smith in January.
"What had angered her, and - it transpired through my investigations with Firecrest Films - other women, was that Lord Rennard was still playing an active role.
"But what most concerned the women we spoke to was that he was attending events involving female candidates.
"That was why Ms Smith and two other women, all current Lib Dem supporters, agreed to do interviews with me. So the decision to go ahead was taken in January, long before Chris Huhne resigned, triggering the by-election in Eastleigh.
"We first approached a senior party figure to tell them we'd done the interview and planned to run with the story the day before Mr Huhne changed his plea [to guilty in the speeding case]."
She used another blog to skewer Clegg's response to the Channel 4 investigation. "What is the difference between an "allegation" and an "indirect and non-specific concern".
"For days, his office has insisted he was completely "unaware" of allegations against Lord Rennard until we broadcast them last week. In fact we gave the party full details on Tuesday, two days before we aired the allegations.
"Mr Clegg says the concerns reached his office in 2008. Bridget Harris, until recently the deputy prime minister's own special adviser, complained to her line manager in 2003."
The issue of sexism in parliament is something of a personal cause for Newman, a former lobby correspondent, she wrote in The Telegraph.
"Perhaps it is too much to hope that one story might help change politicians’ attitudes towards women. But let’s be honest, those attitudes badly need to change.
"And it is not just the Liberal Democrats who have a problem – which perhaps explains why Labour has been relatively quiet about Mr Clegg’s troubles in the last few days.
"One of the women we spoke to, Bridget Harris, who was until recently one of the deputy prime minister’s special advisers, said that although her story happened to involve Lord Rennard, it’s a “depressingly familiar tale”.
"I can vouch for the fact that it is a male-dominated environment, reminiscent of a public school or an Oxbridge college. And yes, there was the odd instance of sexism directed at me: the peer who sent salacious texts; the MP who assumed I was a secretary because I was a woman.
"Get a lot of blokes together in one place, add copious quantities of subsidised alcohol and the fact that homes/wives/partners are far away, and it’s not surprising that the atmosphere is more public school than public service.