In common with anyone who has ever served with the Gurkhas, I think they are marvellous, the very best and most loyal of fighting men. Some years ago, I became involved in a campaign to help the Gurkhas and some people, – quite wrongly and over-generously – credited me with having done a lot to save them. In any event, I would like to think I could always see myself as a loyal supporter of theirs. I am sure, too, that Joanna Lumley admires them every bit as much as I do, and I admire the conviction she has brought to bear in defending their interests. But I have to sound a note of caution. The deal the Gurkhas have had from the government is nothing like as bad as some of the newspaper headlines ("Gurkhas betrayed" etc) will have you believe.

Apart from their outstanding abilities in the field, for a long time the Gurkhas, to put it at its baldest, offered the British govermnment another advantage: they cost less than their British counterparts. They were recruited on the understanding that they would remain Nepalese citizens. They signed up in Nepal, agreed to take their release in Nepal and were paid their pension in Nepal. And a very good pension it was, index-linked and paid after 15 years' service (rather than 21 for a British soldier). This made them well-off in their home country. They had still further support from the Gurkha welfare Trust, to assist in the event of landslides or other misfortunes. It was an arrangement that suited both sides admirably.

The complication comes when we consider the claims of some Gurkhas to live in the UK. In September they won the legal right to retire in the UK. This went against all previous assumptions. They have never had any claim to live here, and that was never the deal under which they signed up. In 1997, most of them chose to switch over to new, UK army rates of pay, a decision the British government honoured. But the result is that those who want to live here cost the Treasury a good deal more than in the past. Surely, this week of all weeks, we need to recognise that such expenditure must have its limits. The Government's decision last week to insist that Gurkhas should have served in the army for 20 years is an attempt to keep sight of reality. It is only recently, when some have seen how comfortably off some retired Gurkhas can be living in the UK, that others have asked to come. Yet this was never the deal at all.

It has been said that we are only talking about a handful of people – a hundred or so. But the government, which has to live in the real world and try to make the books balance, says the cost could be as much as £1.5bn. That sum, let me remind you, would have to come out of the defence budget.

As I say, I have a greater regard for the Gurkhas than anyone. It is not for no reason that they hold a special place in the nation's feelings. I would be mortified by the thought that we might have let them down. Yet I am confident that, rather, we have treated them with fairness and generosity. And I am also confident that a great many serving Gurkhas regard this recent activism as "trade unionism" that discredits their soldiers and is in any event counterproductive.

I suspect that if I didn't know the facts, I would feel as strongly as some of the celebrities who have spoken so vehemently about the Gurkhas. But the facts, not sentiment, are what needs to be considered here.

Lord Bramall was Chief of the Defence Staff from 1982-85, and a colonel with the 2nd King Edward VII's Own Gurkha Rifles from 1976-86