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.
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Mist and fog will affect parts of the Midlands and Eastern England tonight.
A plan to secure the future of Port Talbot steelworks in south Wales will be unveiled to staff on Wednesday.
A National Audit Office report shows that since 2009 the amount of tax paid by the super-rich appears to have fallen by £900 million.