Nick Clegg has launched a scathing attack on Boris Johnson over the Mayor of London's speech on the EU today.
The Deputy Prime Minister said threats to "flounce out" of the union were "deeply irresponsible" and motivated by Mr Johnson's personal ambitions.
The comment about Mr Johnson's ambitions came after he used a speech about Europe to announce his intention to stand for Parliament in 2015.
“I think this speech is more to do with Boris Johnson’s political ambitions rather than what is right for the United Kingdom," the Lib Dem leader said.
"I think it is deeply irresponsible to suggest that we can flounce out of the European Union and I don’t think it's the way that you get the reform," Mr Clegg added.