FRENCH economic superstar Thomas Piketty has joined Labour as an economics adviser, vowing to “expose austerity.”

The Capital in the 21st Century author is the biggest coup for the new six-strong gender-balanced economics advisory committee unveiled by Labour yesterday. Nobel Prize-winning economist Joseph Stiglitz has also been recruited by shadow chancellor John McDonnell to help him set out a credible alternative to austerity.

The willingness of globally renowned economists to advise Labour is a major boost to Mr McDonnell ahead of his conference speech today.

Blairite former shadow chancellor Chris Leslie claimed yesterday that the pair still had questions to answer “about how the sums add up.”

But Mr Picketty, whose 2013 best-selling book exposed capitalism’s inherent inequalities, said he was “very pleased” to be part of Labour’s new project. 

“There is now a brilliant opportunity for the Labour Party to construct a fresh and new political economy which will expose austerity for the failure it has been in the UK and Europe,” he said yesterday. 

Mr McDonnell said the committee, which will meet quarterly, will assist him in developing a “radical but pragmatic and deliverable economic policy for our country.

“Working alongside world leading economists, Labour will present the coherent alternative our country desperately needs.”

In his speech to conference today, Mr McDonnell will stress that a Labour government will “live within its means.”

In a surprise move this weekend, Mr McDonnell backed the Tories’ fiscal charter, committing the government to running a surplus.

But he went on to say that Labour would also invest to make the economy grow and ensure the “proceeds of that growth will be shared more equally.”

An “entrepreneurial” state bringing together “wealth creators and workers” is set to be another theme. Seizing on “Corbynmania,” Mr McDonnell will conduct his own tour of the country to consult the public on Labour’s economic strategy. 

Prime Economics director Ann Pettifor, Sussex professor Mariana Mazzucato, City of London University professor Anastasia Nesvetailova and former Bank of England monetary policy committee member David Blanchflower are the other members of the committee.