David Cameron is demanding a personal apology from Prime Minister Gordon Brown over e-mails sent by an adviser discussing smearing the Tories.
The Tory leader is "absolutely furious" and is calling on Mr Brown to give a guarantee that such messages will not be sent again, a spokeswoman said.
On Saturday, one of Mr Brown's closest advisors, Damian McBride, resigned from his post for sending the messages. Laura Kuenssberg reports.
One-Minute World News 
Bookmark with:
What are these?
E-mail this to a friend