HOW long can Britain stand the current level of casualties in Afghanistan? Probably a long time, shocking though the steady toll has been, and even more with the death of 14 in Saturday’s aircraft crash near Kandahar.

That is partly because of the public perception that Afghanistan, unlike Iraq, is a success. But if that changes, so could support for the mission.

Yesterday’s death of a British soldier in a suicide bomb attack brought the British military death toll to to 37 since the start of operations in November 2001.

The Ministry of Defence classifies only 16 of these as killed in action, while it attributes 21 deaths to accidents, illness, or other injuries.

Perhaps that distinction helps to soothe public anxiety, as it is supposed to do. But the MoD and Nato seem unwise to have got into the “body count” game, regularly citing the numbers of Taleban killed.

After the weekend’s Nato and Afghan operation in the south, a Nato spokesman estimated that 200 Taleban fighters had been killed. But it has generally been impossible to verify the numbers killed, whether militants or civilians. The one constant — with echoes of Vietnam — is that the totals are always far greater than the numbers of Nato or Afghan forces killed.

You can’t keep making such claims without prompting the question of why the Taleban death rate hasn’t yet made much difference. If the answer is that they keep streaming over the Pakistan border, or worse, that far more of the population in the south wants to fight than Britain first thought, then the numbers game is hardly reassuring.

Public support may also be shaken by the row about whether British troops are overstretched and underequipped. That is a constant grumbling backdrop to any engagement, but is taking on new political heat. General Richard Dannatt, the new chief of general staff, has been quoted round the world for his comment: “Can we cope? I pause. I say, ‘Just’.”

Rebutting Conservative attacks, Dr Kim Howells, Foreign Minister, said yesterday: “They (British forces) tell me that the equipment is there,” while calling on other Nato countries to make sure their troops were fully equipped.

Until this year, public concern about British operations was focussed almost entirely on Iraq, not Afghanistan. But Britain’s assumption of the Nato command this summer in Afghanistan has only highlighted the scale of the problem. This year’s opium crop soared by 59 per cent, mainly in the Taleban heartland of the south, the United Nations drugs agency said this weekend.

It is possible that a prime minister would find it even more difficult to pull forces out of Afghanistan than Iraq, given the leading role Britain has assumed in a project that it acknowledges will take years.

Nonetheless, might Gordon Brown, if he succeeds Tony Blair as prime minister, want to change tack? Probably not on the grounds of casualties, at least. The recent intense pressure on Blair from the Labour Party has come over Lebanon, where there have been no British casualties, even more than Iraq, and far more than Afghanistan.

While Brown might not have wanted to get into these wars in the first place, he would surely not want to look weak on them. For all his deliberate inscrutability on future policy, he has suggested at least that much in key speeches about being tough on terrorism.

But that could change if Afghanistan begins to resemble Iraq in its intractibility.

And there are plenty of signs that it could.

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