The headlines were inevitable: “And finally: Sir Trevor McDonald is to retire.” The newscaster has become as much a national institution as the boings of Big Ben that heralded News at Ten. He is as British as roast beef or chicken tikka masala — a remarkable achievement for a Trinidadian who did not settle here until he was 30. Affection for Sir Trev has a Queen Mum-ish quality: not to like him is unpatriotic and rather sinister, it marks you out as the sort of rotter who cheats at Scrabble.

There is a comforting, slightly conservative aura about Sir Trev: no matter how desperate the news from Sudan, the world seems a safer place in which to toddle off to bed after McDonald has smiled “good night”.

He is how we like our English gentlemen to be, but few are: cricket loving, verse quoting, bespoke suited — not to mention impossibly courteous, self-deprecating and infatuated with Britain. It is this “whiteness” that exercises his (few) critics, who accuse him of abandoning his roots.

“I accept their criticism,” McDonald says. “It was entirely deliberate. I did not want to become the token black reporter, blathering about life in Brixton. I wanted to make my way.”

Radicals might consider this selfish from one who earns £800,000 a year. “I take all the blame. But otherwise I would not have gone to places like Northern Ireland and learnt about those problems.” And though he would not dream of saying it, nor would he have become such a role model.

Those in the ’hood alarmed by the assault on multiculturalism by Trevor Phillips, chairman of the Commission for Racial Equality, will find no comfort from the man who tops polls as Britain’s most trusted newscaster.

“Trevor is a friend and I totally agree,” he says. “But I would say something even stronger: if you don’t want to integrate, why come to Britain?” It is a deadly simple point but one white politicos are too politically correct to utter. “I am an unashamed integrationist.”

“McDoughnut”, 64, insists he was “largely spared” racism when he arrived at Bush House in 1969 to work at the BBC World Service, “the United Nations of broadcasting”, though “later in the afternoon you went out into the Aldwych and realised (Britain) wasn’t like that”.

McDonald discovered worse discrimination abroad: in Trinidad, when two blacks were turned away from a country club, and in South Africa under apartheid, where right-wing politicians offered to take him to lunch — only to have enormous difficulty finding a restaurant that would admit a man of McDonald’s colour. It is testimony to his affability that he did not tell them where to stick lunch. Instead he calmly waited for a mixed restaurant to be found.

On his desk in his cramped ITN office a television shows England pulverising the West Indies in the first Test at Lords. He has written biographies of West Indian cricketers, which prompts the obvious question: would he pass Lord Tebbit’s notorious cricket test? “I love to see the West Indians win everything in the world but am terribly indebted to this country. My young son roots for England. I love English life. We West Indians are like international prostitutes,” he laughs, then remembering his diplomatic self, “you’d better not say that or I will be in trouble.”

His love of England might, in part, be a rich man’s contentment. As he says: “When the top job came up (to anchor News at Ten) they gave it to me, so it would be hard for me to complain.” But his feeling for England’s pastoral poetry and the view of St Paul’s suggests a deeper connection.

A more substantial criticism than the sellout charge is that McDonald’s gravitas has allowed ITV to moronify its news, rendering it a tabloid, white van man, cor-what-a-scorcher show; a tawdry end to the career of such a dignified fellow.

“ITV is unashamedly populist,” he counters. “We have all had to adapt. There are many more news outlets in a multimedia environment. But we still try to scale the heights. You hear the charge of dumbing down in every branch of television. If you don’t give people what they want they don’t watch.” Yet compared to the competition, it can look pretty banal.