Labour shadow Chancellor John McDonnell has said he would not fire nuclear weapons to protect Britain and named Das Kapital as his most influential book.

Mr McDonnell, Jeremy Corbyn's effective deputy, also defended his historic support for the IRA saying “everything I did around Ireland was to try to bring about peace”.

During the interview Mr McDonnell also compared himself and Mr Corbyn - both pensioners - as like “two old geezers from Last of the Summer Wine touring the country”.

Asked by the New Statesman “would you press the so-called nuclear button, if you were prime minister?”, Mr McDonnell said: “No.”

The comments risk reviving the row over Mr Corbyn's refusal to say that he would fire nuclear weapons to protect the UK. During the general election last year, the Labour leader was jeered and heckled by a live television audience when he said he would not fire nuclear weapons first to defend Britain.

In the wide ranging interview Mr McDonnell - who will speak from the platform at the TUC annual conference next week for the first time - said that Karl Marx's Communist tract Das Kapital was his most influential book.

He said: "It has to be Das Kapital. Francis Wheen’s description of Kapital is brilliant. It is not just a piece of economics, it’s a work of literature as well."