Karl Marx is “back in fashion,” Labour’s shadow chancellor John McDonnell has declared on his big day of his keynote economics speech to the Labour party conference.

He said the architect of socialist economics still offered one of the best analyses of how capitalism worked – more than 130 years after his death.

Mr McDonnell insisted that whether or not people agreed with his prescriptions for dealing with the system but said his theories offered “interesting analyses” that have now become mainstream thinking.

He told BBC Five Live: “If you look at our capitalist system, one of the definitive analysts of how it works – not whether it is condemned, or whether it is right or wrong, just the mechanics of how it works, when it was formed and how it would be developed – actually was Marx.

"If you look at most of the institutions that are teaching economics today. Marx has come back in to fashion because people have gone back to his analysis of just the basics of how the system works.

“People might disagree with his conclusions about what to do with the system, but actually to understand how the system works he comes up with some interesting analyses that have been built in to traditional and fairly classical economics.”

He was speaking as he set out Jeremy Corbyn’s economic policy, promising to launch a review of all the UK’s tax policies and a rethink of the Bank of England’s mandate.