When Nick Clegg announced on Wednesday morning that the next caller to his weekly LBC phone-in show, Call Clegg, was "Cathy in Dulwich" he may not have realised it was Channel 4 News presenter Cathy Newman. "It's Cathy Newman here from Channel 4. I'm what you might call a self-appointed detective," she told him. If Clegg was taken by surprise, he barely blinked. Newman, not surprisingly, wanted to know about the circumstances of the departure of the Lib Dems' former chief executive, Lord Rennard. "At the weekend you said Lord Rennard quit on health grounds. Now you appear to be accepting his behaviour was part of the reason he went," she asked. "LBC, Channel 4, gosh my head is spinning with the number of media outlets involved here," said Clegg. "Anyone can ring in," replied LBC breakfast presenter Nick Ferrari, raising the spectre next week that the show might resemble a Westminster lobby Q&A. Anyway, back to Rennard. "He left on health grounds but of course the issues of his inappropriate behaviour were in the background, of course they were," said the deputy prime minister. And with that, it was time for a break. "We'd love to do an interview," added Newman. If they do, maybe Ferrari can ring in with a question.