Nick Clegg has demanded an apology from Theresa May over the "false and outrageous" claim that he has put children at risk with his opposition to the so-called snoopers' charter.
In her speech to the Conservative Party conference on Tuesday, the home secretary said the Liberal Democrats decision to block giving new powers to the intelligence services had caused a "crisis in national security". May said several cases had to be abandoned including thirteen "threat-to-life cases" involving children.
Clegg said the "absolutely appalling" speech was a "new low point in coalition relations". Speaking on LBC radio this morning, the deputy prime minister said "it was one of the most misleading and outrageous platform speeches I’ve heard in conference seasons for a very long time".
He added: "To say about another politician, particularly someone you are governing with, that you are putting children at risk, when it’s not true, is a level of outrageous misinformation that I have not witnessed in the four and a half years I’ve been in this government."
According to Sky News, May intends to write to Clegg in "strong terms" and will refuse to offer an apology.
The explosive row comes ahead of the Lib Dem conference in Glasgow, the party's last gathering before the general election in 2014. The party is likely to spend even more time than normal trying to differentiate itself from its Conservative Party coalition partners.
Despite today's coalition row, Shirley Williams, the veteran Lib Dem peer, told The Times that the party was too submissive in the first 18-months of the coalition. The party "went along with almost everything the Tories wanted," she said.
Her view is shared by many Lib Dems, who fear voters will punish the party in 2015 for its decision to join with the Tories and put David Cameron in No.10.
May's announcement that she wants to introduce new powers to ban extremists from appearing on television and restrict their use of the internet has also been sharply criticised by some of her fellow Conservative MPs as an attack on free speech.
Writing in the Daily Telegraph today, Dominic Raab said the move "erodes basic principles of freedom won’t make us safer". The former Foreign Office lawyer said it was "contrary to our tradition of free speech"
"Banning people from the internet and social media – who have not been found guilty of any crime, and are not threatening terrorism, violence or disorder – won’t improve public protection," he said.
An attempt to prevent extremists appearing on TV has echos of the 1980s ban on Gerry Adams and other Sinn Féin officials. The ban, in place when Margaret Thatcher was prime minister, was widely ridiculed as playing into the hands of republican groups.
May, seen as likely to challenge for the Tory leadership once Cameron steps down, was repeatedly compared to Tatcher following her conference speech. Michael Gove branded her the new "iron lady". And many, including the Daily Mail, noted the striking similarities between May's speech and one given by Thatcher.