Paul Nuttall, UKIP's deputy leader, says any election pact with the Conservatives would be "very difficult" while David Cameron heads up the party.
"You really can't believe a word he says on the European Union and he's also a guy who called us closet racists," he said.
More top news
Staying mild overnight with a sunny start forecast for most of the UK.
Scientists claim bubbling magma is behind the 'man in the moon' image rather than an asteroid strike
Our Political Editor Tom Bradby has been tackling readers' questions about David Cameron's conference speech.