David Cameron has pledged an in-out referendum on Europe in 2017, and says he will not lead the country if he cannot guarantee to provide the vote.
The prime minister's comments, made on BBC One's The Andrew Marr Show, suggest he would not lead a minority government should the Conservatives fail to secure a parliamentary majority at the 2015 General Election.
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Rescue workers are at the site Sunday morning trying to cut open mangled coaches.
Despite chilly temperatures it will be a mostly dry day, and milder than yesterday.
The Sunday Times alleges a missile malfunctioned after launch during a routine test of the UK's nuclear deterrent last year.