The House of Commons broke into roars of laughter as former development minister Sir Alan Duncan branded Boris Johnson "Silvio Borisconi".
Sir Alan, appearing to compare Johnson to former Italian leader Silvio Berlusconi, signalled he would be joining the "stop Boris" campaign to block him from taking the Tory leadership.
Silvio Borisconi! I don't know who said it but thank you for making me laugh so hard. No idea that PM's question time was such a hoot!
-- Elaine ClosEUre (@MrsBlinkle) June 29, 2016
Sir Alan said: "Moving to more cheerful matters, would you educate the House from your experience as Prime Minister on how in terms of their country's reputation and success he would compare the undemonstrative competence and dignity of Angela Merkel with the theatrical and comical antics of Silvio Borisconi?"
So "BoJo" is done, now its Silvio Borisconi ???
-- Bilo & Biggles ? (@bilo_biggles) June 29, 2016
"Silvio Borisconi" nice one from Alan Duncan not like him to be funny #pmqs
-- David Clelland (@Dclell) June 29, 2016
Cameron said he would stay out of the Tory leadership contest, before joking: "I was given lots of advice on becoming Prime Minister, one of them was not to go to a party with Silvio Berlusconi and that's one bit of advice I took and stuck to."
Johnson has faced criticism for failing to set out what happens next despite being the figurehead for the Brexit campaign and favourite to succeed David Cameron as Tory leader and prime minister.
Silvio Borisconi ??????????
-- Ian (@rutherian) June 29, 2016
Many people, including myself, wishing they had thought of Silvio Borisconi
-- Shaun Linden (@ShaunLinden) June 29, 2016
Well played, Sir Alan.