Bernard Ingham: We can be Obama's reliable and realistic friend

This remark holds out the promise of a realistic relationship with America. While man-for-man our troops are probably still the best in the world, in spite of the attentions of Gordon Brown, we carry nowhere near the firepower of the US. And economically we are at best only about a fifth of the somewhat reduced might of America.

But military and economic clout is not everything in this game. Nor necessarily is a personal rapport, though it helps. What matters is whether there is a mutual trust between the two leaders and a recognition on both sides that candidness is the best policy.

So what they should be doing today is trying to forge that trust and recognise the value of calling a spade a bloody shovel when they meet.

Margaret Thatcher, with her innate tactlessness, was incapable of anything but frankness. Indeed, she argued that you were not much of a friend if you did not give others your best advice, however unpalatable it might be.

Fortunately, she had in Ronald Reagan a man of such sunny disposition that he was able to take all she could throw at him. And she threw a lot over the initial American equivocation about the recovery of the Falklands, the invasion of Grenada, the abolition of nuclear weapons (which he offered Mikhail Gorbachev at Reykjavik), the Star Wars concept of defence in space and, of course, his mounting deficit as he refused to raise taxes.

Reagan is reputed to have pleaded in the midst of her handbagging him over Grenada: "Gee, honey, don't go on so."

But he knew which side his bread was buttered. Europe was then the busted flush it still is today. Obama, 18 months into his presidency, must know the truth of this. Only the UK is a reliable and durable ally.

He may not strictly or foreseeably need us, but he would be mad to throw away our goodwill and support.

Unfortunately, the timing of this first one-to-one summit could be better. While Cameron has made an impressive start to his premiership, Obama has lost his glitter.

The president faces the possibility of a thrashing in the mid-term elections and reveals anything but a confident personality.

His grubby behaviour over the grossly exaggerated BP oil well leak – as are all environmental disasters these days – has been frankly appalling.

So we have a touchy, twitchy president face to face with the confident optimism of the old Etonian. Cameron needs all the social grace of his upbringing to build the trust based on plain speaking that the world needs from these two.

It is a formidable test for him because, apart from BP, there are a lot of potentially divisive issues crying out to be addressed – the "mistaken" release of the Lockerbie bomber, Iraq and Afghanistan – indeed the entire Middle East mess, including Iran – terrorism and the global economy, where Cameron is a more enthusiastic cost cutter than Obama.

The temptation in all of this is for both sides to paper over the cracks and strive at their final press conference to prove their first summit was a resounding success.

I know. I've been there – to 31 European, 11 G7 and two NATO summits, six Commonwealth conferences and heaven knows how many bilateral meetings with Jimmy Carter, Reagan, George Bush senior and the likes of Gorbachev, Francois Mitterrand and Helmut Kohl.

It is a mistake to try to stretch the truth. It is better to show that you have a businesslike relationship that is strong enough to address sticky problems in a constructive way. An ounce of realism is worth a ton of spin at summits.

So I hope that Obama and Cameron will acknowledge the problems that beset them and demonstrate their willingness to work together to solve them. A determination to co-operate will go a long way in convincing many that Obama is a bigger man than we are beginning to fear and that Cameron is a real asset on the world stage.

It may well be that Britain is still living on its long lost imperial glory. But it still has a lot to offer the US – and not least reliable and realistic friendship.