Conservative leader David Cameron must not become "obsessed" by Tony Blair's departure, his predecessor Iain Duncan Smith has warned.
Duncan Smith said the Tories should put their 'house in order'
Mr Duncan Smith, who was ousted in 2003, said the priority was to "put the squeeze" on Liberal Democrats.
Policies had to help people who might never vote Tory, he told BBC Radio 4's World at One.
Areas like family breakdown, drug addiction and pensioners living in fear were the party's "battle ground".
Mr Duncan Smith, who is heading the new Conservative Social Justice Commission, said: "We have to show we understand that a party that governs has to really have a strong message for people who may never vote for it but who really have problems."
He said of Mr Cameron's attitude to Mr Blair's departure: "He should not be obsessed by it.
"What we should do is put our own house in order right now and what we have got to understand is we have to occupy the ground in people's sense of us that allows us to put the squeeze first and foremost on the Liberal Democrats."
Earlier this month, Mr Cameron urged Lib Dems to defect to the Conservative Party, claiming it stood for "liberal values", such as green policies, localism and economic deregulation.
But Lib Dem leader Charles Kennedy said: "If David Cameron actually meant what he was saying, perhaps he's the one who should be joining the Liberal Democrats and the Conservatives should be looking for a new leader."
Mr Blair's predecessor as Labour leader, Lord Kinnock, told World at One he believed the Prime Minister had made up his mind when to step down but had not told anyone.
He added that tough times ahead might make him more determined to stay on.
Meanwhile, former Liberal Democrat leader Lord Steel said Mr Kennedy would stay on until at least the next election.