The former prime minister, John Major, has given guarded support to Michael Portillo's campaign to become Conservative leader.

Whilst he stopped short of issuing a formal endorsement, he cited the shadow chancellor as a big hitter who would be capable of leading the party.

Major, interviewed on Breakfast with Frost, said Portillo had benefited from a period out of politics.

"Michael seems to have gone on a long journey from where he was to where I was, and I thoroughly welcome that," he said. "It is a good idea to reinhabit the centre ground and I think the things that Michael is saying is an indication he has learnt a lot."

Major also called on lesser-known MPs considering running for the Tory leadership to think again.

"I personally hope that some of the marginal candidates, some of the more inexperienced candidates, will decide that this is not the time for them to throw their hats in the ring. I think they should sit out this election and let more senior members of the party contest the election and determine who is going to be leader," he said.

The former prime minister also warned that the party would become the "permanent opposition" if it continued to march to the right. "What the Conservative Party has got to do is to recapture the understanding that it wins elections from the centre-right," he said.

"The elections are won in the battle for the centre, we win from the centre-right but we have to engage with the Labour Party in the centre as well - over health, over education, over transport, over the issues that really determine the votes of most people in this country."

Major's comments came as Portillo, the only candidate to have thrown his hat into the ring so far, said he wanted to end the Tories' on-going war over the European question.

Writing in the Mail on Sunday, he said: "We mustn't go on with a Berlin Wall between those, like me, who believe that Britain should have its own currency and those who take a different view. There's no reason why we cannot draw on the talent across the party and so offer the country our best possible team."