In some ways, it is difficult to write a short biography of journalist and broadcaster Alistair Cooke. Not because he didn't lead an interesting and involving life, because he did, but more because (unlike film stars, fiction authors and so on) his career and fame were centred on one pivotal achievement – but it really is quite some achievement.

But, before we get there, some background – Alistair Cooke was born in Salford, Manchester on 20 November 1908. He attended Blackpool Grammar School, and from there went to Jesus College, Cambridge where he studied English and gained an honours degree, then in 1932 travelled to America to undertake graduate studies at both Yale and Harvard.

He returned to England for a short period between 1934 and 1937, during which period he served as the BBC’s film critic, and made a weekly broadcast for NBC, called London Letter. When he went back to the US in 1937, he began a long career as an overseas correspondent, with The Times, and has long been considered the most respected expert on American affairs in the British press. He became an American citizen and married his second wife, painter Jane White in 1941, having divorced from his first, Ruth Emerson, with whom he had one child, sometime earlier. He and White also have one child.

In 1945 Cooke joined The Guardian (then the Manchester Guardian) first as its United Nations correspondent, then, in 1948, as its Chief American Correspondent a position he held until he retired it in 1972.

It is as a broadcaster, however that he is chiefly known and loved – and quite rightly. He had enjoyed presenting the London Letter, and from America, he badgered the BBC to take up the idea, except in reverse. At first, he met with little success. His first series, Mainly about Manhattan was broadcast sporadically and lasted until war broke out. Alistair was keen to continue the idea during the war although the BBC were less so. He tried to persuade them:

"I believe it is a very grave error not to have a weekly talk from this end, of America and the War. I know it is an assignment of maximum delicacy. But the alternative is something that makes me lie awake at nights: it is the miserable, and by no means impossible, prospect that from silence may develop a habit of recrimination between the two countries."

But the BBC, it seemed, were having none of it. Their reply was terse:

"Whilst I think there is a need for the USA to understand the British situation, I do not feel at this stage there is an equivalent need for us to understand the American point of view."

A lesser man would have given up, but Cooke continued to campaign, and was eventually successful, playing a large part in the well regarded American Commentary which ran until the end of World War II.

Then, on March 24th 1946, he broadcast his first Letter from America. This fifteen minute weekly broadcast took prominent events in American news from the preceding week and contextualised them, explaining why they were important to Americans: historically, socially and/or personally. Cooke always understood the American psyche, but more than that, he understood the British psyche too, and knew how to make the one explicable to the other. In a warm, conversational voice he gently worked to undo misconceptions between the two nations, iron out prejudices, present things in a way that they made perfect sense – something that is often difficult.

The programme was still going strong, 58 years later, making it the longest running single programme in broadcasting history. It’s almost beyond imagining - Alistair Cooke, over the course of this programme talked to his audience (and it was a huge audience worldwide, Letter from America was the most popular BBC radio programme all over the world and reached as far as the BBC does, which is everywhere) for a solid month giving well-researched, witty, and engaging insights into America, American life and the American people.

Cooke was always a passionate crusader for Anglo-American harmony and while it is hard to say exactly how successful he was in promoting it, many believe that Letter from America made a real and discernible difference to the relationship between the UK and the USA.

Former American Ambassador to Britain, Raymond Seitz, says "I think he has provided comfort that things which appeared to the British eye bizarre or impetuous or ramshackle - all of which we Americans are - he could put it all in a context, in a wonderful, conversational, matter-of-fact way. He could say, "Don't get excited about this. That's the way we do things over here."'

How much influence can one radio programme have? Well, Queen Elizabeth II, who, in 1973, awarded Cooke an honorary knighthood for services to Anglo-American relations has expressed wonder at how directly he could communicate to his audience week after week. British Prime Ministers Harold McMillan and Winston Churchill were both known to be regular listeners, as were Ronald Reagan who recorded a special 80th birthday tribute to Alistair, and ex-President FW de Klerk of South Africa. In 1974 he was invited to address the United States Congress on its 200th anniversary – there’s no doubt that Letter from America is influential.

And why did it remain so popular to the last show? Part of it had to be Cooke’s voice – still warm, melodic, and rich even at the age of 95. Part of it was his style – lucid, but a true storyteller’s approach, taking an event and slowly adding disparate elements and weaving them together until they illuminate each other and his central point, so that the listener is drawn in, waiting for the ending and receptive to the message. The final part must be the humour. In 'The Sugar Pill', commentator and critic T.S. Matthews writes of Cooke, "Alistair Cooke… as an American (by adoption) naturally spends most of his time laughing. One reason he finds the United States inextinguishably amusing is that he is in love with the country, in a way that perhaps only a converted Britisher can be."

Alistair Cooke and his Letter from America – they can’t really be separated -- became an institution, in the best way, and it’s hard for their audience, most of whom have, like me, grown up listening to it, to imagine radio without them. Alistaire Cooke's last "Letter" was broadcast on 20 February 2004, and he died, just over a month later, on March 30th, aged 95. I suppose it was inevitable that it couldn't last forever – but I think the world would be a better place if it could.