Tony Blair has called for new political leadership from the “strong progressive centre” and confirmed his institute is developing a raft of policies to encourage such leaders.

The former prime minister insisted he had not given up on Labour despite his concerns of it being “in the grip of the hard left”.

Speaking to BBC Radio 4’s Today programme, he admitted he was trying re-energise the centre ground of British politics, which he claimed was being abandoned by the two main parties.

“If you leave between the Brexit-dominated Tory party and a hard-left Labour party vast uncultivated centre ground, at some point someone is going to come along and cultivate it,” he said.

At the weekend the Observer revealed that plans for a new centrist party had attracted £50m of investment. Blair denied trying to form a new party, saying: “I’m not advocating it or involved in such a one or certainly not running for its leadership at this or any stage.”

But he said such a plan should not be derided by the established parties. “What is most sensible is for both of the main parties to realise they can pour scorn on people who are thinking of these things, but ultimately they’ve got to understand there is a constituency in this country which is socially liberal, in favour of strong methods of social justice, but also believes in a well-run enterprising economy.”

Blair lamented the lack of political leadership from centrists. He said: “The really depressing thing about western politics at the moment is that the leadership of what I would call a strong progressive centre is just not there, it is lacking.

“And the result of it is you have rightwing politics going into anti-immigration nationalism and leftwing politics going into sort of anti-business old form of statism, and neither are the answer to the problem of the future.”

He confirmed that his Tony Blair Institute for Global Change was developing a platform for any emerging centrist politicians to utilise.

“What we are is putting together is a policy platform … that anyone in politics could take if they come from the open-minded approach to the problem, which says that globalisation is essentially a good thing, not a bad thing, but its risks have to be mitigated … My institute is looking at things like housing, infrastructure, what’s the right tax and spending policy.

“It is not a manifesto because it is not for a political party – it is for people whether they are in the Labour party, Conservative party, Liberal Democrats, wherever, who can see the way politics is developing in the is country and who think there must be a better set of policy ideas for the future.”

He added: “I have got no infrastructure for building some political party. But what I fully own up to is trying to create the sort of centrist policies that I think can rekindle optimism about the future, since I think that these lurches to the right and to the left are basically the politics of pessimism.

“Starting a new political party is incredibly difficult. I’m focused on one thing, which is what are the right ideas.”

“We have got an old-fashioned Conservative party and a Labour party that’s got frankly reheated politics from the days I remember when I was a student. I don’t think either of those things answer the challenge for the country.”