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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Angela Merkel has taken a step towards forming a cross-party coalition and ending months of political deadlock.
Thousands of women's rights campaigners have held a rally outside Downing Street.
Hundreds of people are visiting St Joseph's Church in Limerick to pay tribute at the church wake for Dolores O'Riordan.