Election 2015: David Blunkett warns of SNP 'tsunami'
Former Labour Home Secretary David Blunkett has compared the SNP to a "tsunami sweeping Scotland".
Mr Blunkett, who has retired as an MP after 28 years, told BBC Radio 4's The World at Onethat voters in Scotland had "stopped listening... to even rational argument".
Polls suggest Nicola Sturgeon's party could take around 50 Commons seats at next week's general election.
The Scottish Nationalists won six Westminster seats in the 2010 vote.
Mr Blunkett said since he was first elected to Sheffield City Council 45 years ago, he had "never seen anything quite like what we have at the moment".
He said one of his former researchers was standing in "what used to be a safe Labour seat" and was "fighting to the very end with what can only be described as a tsunami sweeping Scotland".
"I think people have stopped listening. I think their minds have switched off to even rational argument," he said.
"It's extremely difficult to win that back.
"People aren't even prepared to take leaflets or to engage in discussion.
"It's as though a great part of the Scottish nation have switched off and it's so dangerous for the union and for the future of Britain as a whole."
Scottish Labour leader Jim Murphy has described the SNP as "David Cameron's little helpers" because of its potential impact on Labour's vote in Scotland.
The SNP says it will use its influence at Westminster to oppose austerity and keep David Cameron out of Downing Street.
Mr Blunkett said Labour leader Ed Miliband's "greatest challenge" if he became prime minister would be to address the need for "something different to the normal run of politics".
He added: "We all went through the horror of the 1983 election when Labour was massacred in the polls, but people were still arguing about policy and values and now we have a situation where Labour could win literally scores of seats in England and Wales and see themselves unable to offer a majority Labour government because of what's happened in just one part of the United Kingdom."
He said the next Parliament would be about "reshaping the way in which Westminster operates" and that a Labour government would "have to reach out across the political divide" to all of the other parties.