Mary Dejevsky: This is Cameron's Ecclestone moment

In spending his half-term as Britain's carpetbagger-in-chief, he has shown breathtaking misjudgement

Maybe we will wake up this morning to learn that the SAS, with French air force cover, has mounted a daring rescue of British and other EU workers stranded in the Libyan oilfields. Maybe Our Man in Tripoli will tell us how he has been working around the clock, rallying a tiny number of embassy staff to answer phones, charter planes and organise secure transit to the airport – which is why he has been silent until now. Maybe, too, we will discover that HMS Cumberland has managed not just to pick up a couple of hundred fleeing British nationals, but to land tonnes of medical aid for Benghazi, along with teams of volunteers to help. Maybe, even, the Prime Minister will be there to wave the flag.

In which case, much of what you are about to read will be, if not irrelevant, then overtaken at least temporarily by pride in the Great British can-do spirit. So far, though, this seems to have been a pretty sorry saga, even if the confused and highly volatile situation in Libya has to be cited in mitigation. Law and order has broken down in many parts of the country. A stubborn and desperate warrior-leader has committed himself to a last stand. In such circumstances, not organising a timely evacuation has to be seen as a serious practical failure, but not a crass, clodhopping and potentially career-breaking mistake.

Unlike David Cameron's extraordinary decision to spend the past week as he did. Rather than staying at home to steer the Coalition through one of the most acute foreign policy crises for years – a crisis, moreover, thanks to Tony Blair, with a particular British angle – he chose to proceed with a multi-day jaunt to promote British trade, including weapons sales, in, of all places, the Arabian Gulf. It was not even as if the Gulf had been spared the unrest elsewhere. Bahrain's streets had been stained with the blood of democracy protesters just days before.

Let me state, for the record, that I do not approach this as a foe either of arms sales per se or of David Cameron. Weapons are something Britain is rather good at producing, and arms sales – I fear – have a place in our exports, especially in view of the cutbacks in our own defence spending. Nor do I have particular inhibitions about selling, for instance, tear gas to unsavoury regimes. It can be argued that lack of training and equipment for non-lethal crowd control may be to blame for some of the most egregious atrocities committed by governments against their people. Would the Chinese leaders of today, I wonder, field tanks against protesters, if they had water cannon and tear gas in reserve? Consider Egypt.

As for Mr Cameron and his Coalition, I have defied the verbal slings and arrows of left and right to defend them. I liked the boldness with which Mr Cameron proposed the Coalition and the similar boldness with which Nick Clegg accepted. I lament the Liberal Democrats' U-turn over university fees, but it was inevitable once they went into Coalition. I applaud the repeal of repressive legislation and the attempt, albeit timid, at electoral reform.

I find the case for cutting the deficit unimpeachable; the actions of mostly Labour local authorities in (to my mind, deliberately) exaggerating "the cuts" unconscionable, and the benefit reforms as generally making sense. There are too many incentives not to work; testing for disability payments was lax. That housing benefit allows non-working families to live in accommodation many working families could never afford is an absurdity of the system. So far as I am concerned there is a conclusive case for reform, and the Government should get on with it. I sigh each time some clever piece of special pleading on behalf of this or that hard done-by lobby group lands in my inbox. I have never really got to grips with the "Big Society", largely because I do not think Mr Cameron realises how many people are "time-poor", as well as lacking his family's means, but for me his sincerity was never in doubt.

That was then. On Monday, it was suddenly reported that he was on his way to Cairo, the first national leader to visit Egypt since the fall of Mubarak. Well, hats off to his public relations team for dreaming that one up, and to the Foreign Office or whoever for making it happen. They clearly excel at getting prime ministers into "difficult" countries fast, even if they find it harder to get lesser mortals out. His next stop was Kuwait, to celebrate – so we were told – the 20th anniversary of its liberation, the mission accomplished of the first allied war on Iraq.

In fact, for the best part of two days, if you had had only the Prime Minister's media operation to go by, you might have thought the sole purpose of his trip was to celebrate the new dawn of Arab democracy. But it soon transpired that this was a long-planned trip that had originally had nothing to do with Egypt and democracy, but an awful lot to do with more materialistic salesmanship. While Mr Cameron had the delicacy to stay away from the region's biggest arms fair, Idex 2011 in Abu Dhabi, all the sweet words in Cairo could not disguise the greater purpose of his tour.

Given that William Hague had been in the region only 10 days before – when he pulled a similar trick, using Tunisia as his high-profile democracy launch pad, before proceeding to (pre-protest) Bahrain and the standard genuflection tour around the Gulf – you have to ask, at very least, whether it was really necessary for Mr Cameron to show the flag again so soon. Is the country – or the Conservative Party – really so strapped for cash that the Prime Minister has to demean himself in this way? Surely, the all-encompassing uncertainty would have been pretext enough to call the visit off.

In choosing to spend his half-term as Britain's carpetbagger-in-chief, the Prime Minister showed quite breathtaking misjudgement. It is not just that he decided to leave the country at a time of great international turmoil. Nor is it only the embarrassing coincidence of promoting British weapons, even as some one-time purchasers were putting them to ignoble use. It is that the nature of this misjudgement fits all too well with previous hints of Mr Cameron's flaws.

Bill Clinton's history of womanising made the Monica Lewinsky affair that much more dangerous. George Bush's early blend of superficiality and zeal brought him the debacles of Iraq and New Orleans. Tony Blair's predilection for celebrity and spin were fatefully foreshadowed in the Bernie Ecclestone affair. Why did Mr Cameron decide to go ahead with his Gulf trip, while wrapping it in the veil of democracy? Because he placed loyalty to friends before his domestic responsibilities, because he saw a chance to shine, and because his brimming self-confidence told him he could get away with it.

This episode is dangerous precisely because it supports early evidence of weaknesses in Mr Cameron's character. If the political price at home turns out to be as high as the popular response so far suggests, he will have more than a delayed evacuation of British citizens to be "incredibly sorry" for.

m.dejevsky@independent.co.uk