Oxford economist accuses Theresa May of 'lying' when she quoted him during PMQs

Academic suggests prime minister deliberately misquoted him in order to 'gain political effect' in attack on Labour

A leading economist has accused Theresa May of "lying" during Prime Minister's Questions, claiming she deliberately misquoted him.

Simon Wren-Lewis, a professor at Oxford University, strongly denied the prime minister's suggestion that he had said the figures in Labour's last manifesto "did not add up".

The claim appeared to be "a deliberate lie told to gain political effect", he said.

Ms May made the comment during a clash with Jeremy Corbyn at PMQs on Wednesday.

She did not directly name Mr Wren-Lewis but referred to a chapter he wrote for a book, titled Economics for the Many, that was edited by John McDonnell, the shadow chancellor. Mr Wren-Lewis is an informal adviser to Mr McDonnell.

During an exchange on funding for public services, the prime minister brandished a copy of the book and said: "If [Mr Corbyn] wants to talk about figures, I have a book here that is edited by the shadow chancellor. In it, an article by an economic adviser to the Labour Party says about its last manifesto that 'the numbers did not add up'.

"I have even got the page marked. It also said that this was 'a welcome feature' and 'largely irrelevant'. Well, it may be irrelevant to [Mr Corbyn] and the shadow chancellor, but it is not irrelevant to the people whose taxes go up, whose jobs are lost and whose children have to pay Labour’s debt."

Mr Wren-Lewis hit back within minutes, denying that he had said Labour's figures were wrong. Instead, he said, he had argued that claims by the Institute for Fiscal Studies that the party's costings contained "factual mistakes" were irrelevant.

He wrote on Twitter: "Apparently the prime minister quoted me saying about Labour's 2017 manifesto 'the numbers did not add up'. In fact I said 'let us suppose the IFS was correct' and examined consequences. I have never taken a view on whether they did/didn't add up. If that is what she said, she lied."

In a blog post titled "The day Theresa May lied in parliament about something I wrote", he continued: "The point I wanted to stress was that it didn’t matter if the IFS were right that the numbers didn’t add up, because the fiscal stance was good for the economy, and could well satisfy Labour's very good Fiscal Credibility Rule."

Of the prime minister's comments, he said: "Was this an unfortunate case of misreading? It seems extremely implausible. I’m certain that when the PM or more probably some adviser misquotes someone in a draft PMQ response, someone - possibly even the person themselves - checks that the quote is correct. You have to have serious comprehension difficulties to misunderstand the meaning of 'let us suppose'."

He suggested Ms May's claim was "a deliberate lie told to gain political effect" but said he would be willing to accept it was "an honest mistake" if the prime minister or someone from her team could explain how it happened. 

He said: "In the scheme of things the issue is very minor, but the prime minister lying whatever the context should be important. But the sad thing is that no one is surprised by this kind of thing any more.

"We in the UK look at Trump’s lying with horror and think this is something uniquely American. But this government has been pulled up countless time for misleading the public by misusing statistics and of course the lies of the Brexiters are shameless."

Mr Wren-Lewis said he had asked the Conservative Party for an apology but was "not holding my breath".

The matter was raised in the Commons by Peter Dowd, the shadow chief secretary to the Treasury, who suggested Ms May should apologise.

Making a point of order, he said: "During Prime Minister’s Questions, the prime minister asserted that the respected Oxford economist and professor, Simon Wren-Lewis, said, in reference to Labour’s manifesto, 'the numbers did not add up'.

"However, Professor Wren-Lewis disputes the accuracy of those remarks."

Quoting the academic's tweet, he added: "Would it be appropriate for the prime minister to come back to this House to correct the record and apologise to the renowned professor in question?"

The deputy speaker, Eleanor Laing, said she was sure Ms May's comments were made "in good faith" and that it was not her job to assess the accuracy of claims made in the Commons.

No 10 has been contacted for comment.