World ends when you can't hear Naughtie

The end of civilisation will be marked by a deathly hush from James Naughtie and his colleagues on the BBC radio programme Today, commanders of Trident submarines have been told.

In a preface to a new book on postwar politics, Muddling Through, out today, contemporary historian Peter Hennessy pays tribute to Radio 4 as part of the national identity.

But he then reveals a chilling secret about the procedure for war.

"I was tickled (in a grim way) rather than surprised to learn that the final check the commander of a Royal Navy Polaris or Trident submarine would make, deep under the waters of the North Atlantic, to determine whether a United Kingdom still existed, before he opened his sealed orders on retaliation after a pre-emptive nuclear strike, would be to tune in to the Radio 4 Today programme.

"If, after a highly secret number of days, there is no Jim Naughtie, John Humphrys, Anna Ford, those last instructions from a by-now deceased Prime Minister would be opened."

Mr Hennessy, Professor of Contemporary History at Queen Mary and Westfield College, London, describes the procedure as "a final if macabre tribute to a broadcasting service sans pareil".

"I used sometimes to wonder if Mrs Margaret Thatcher as Prime Minister knew about this particular subsidiary function of Today, a programme of which she was a regular but rarely satisfied listener."

Professor Hennessy said yesterday: "If the Trident commander could not pick up Today, that would be that. He would then have to decide whether to launch the missiles, or go off to New Zealand. He would know that there was no point in going back to base, in Faslane."

Mr Naughtie told The Independent that he certainly did not know of the Trident commanders' orders to listen in to Today.

"I suppose we've always known we have listeners everywhere," he said.

"It now appears we have them in the depths of the ocean. I think that may be marginally surprising, since some people don't appear able to get decent reception in the Highlands of Scotland, and they can get it at the bottom of the various oceans of the world."

But he added: "For their sake and for ours, I hope they never have to go for too long without Today."

In his book, which includes a number of his Radio 4 broadcasts, Professor Hennessy says that the decision to launch a nuclear strike is otherwise held exclusively by the Prime Minister of the day.

Lord Callaghan, the former Labour prime minister, told him in one programme: "I don't think I ever sat down and contemplated [the decision]. It was one of the things that one had to face for many years, and I took part in exercises that would lead up to the point where you either discharged the missile or you capitulated.

"Those exercises were not very pleasant occasions, but it's one of the matters that you have to live with, and I found no difficulty in living with it, although I would have found great difficulty in having to take the decision.

"Nevertheless," he continued, "that is your job, that is your responsibility, and I would have taken whatever decision was appropriate."