The British, said a senior RAF officer this weeks, still consider themselves to be something of superpower.

"It comes as a shock to find that we're actually a medium-sized country, a junior partner to the US and our air force is tiny," he said.

The comments highlight growing doubts about the capability of the British military to meet public and political expectations in the Balkans.

Prime Minister Tony Blair has been forthright in justifying military action and may increase Britain's commitment. But some people are asking how can the armed forces cope?

As the military machine undergoes implementation of the Strategic Defence Review (SDR), designed to streamline Britain's military might, defence experts say the Kosovo crisis has caught them at a bad time - and at full stretch.

A long way second

Britain's military commitment in the Balkans is second only to that of the US - but it is a long way second. The RAF have been most heavily involved with 30 aircraft, the Royal Navy has five ships involved and the Army 6,500 has troops in Macedonia.

This has to be put in perspective. The air force is at its highest level of operations since the Gulf War in 1990-91. The ships in the Balkans constitute 20% of the total currently at sea, and the Army personnel in Macedonia are the second largest current deployment - second to Northern Ireland and ahead of Bosnia.

The SDR forced cutbacks on all the services - but also focused the forces on expeditionary warfare such as the conflict in Yugoslavia.

Bruce George MP, Chairman of the Defence Select Committee, said the timing of the conflict could be a good thing.

"The SDR has been put to the test more swiftly than anyone thought. Costings in the SDR were taut - but if there is just cause for action then the cost must be borne.

"The timing of the Kosovo crisis will test assumptions made in the review - and whether we have enough troops will depend entirely on the level of commitment from the government."

RAF bears brunt

Nato's policy of air strikes focuses public and political expectation on the RAF. But weather has hampered its operations, with successful strikes only taking place on 16 nights out of 26.

Harrier pilots have been hampered by weather

Since the end of the Cold War, the RAF's fast-jet squadrons have been cut by half - and they have faced more cuts in the ongoing defence review. The service has concentrated on honing specialist skills such as low-flying Tornado bombing runs and using the flexibility of the Harrier.

In this conflict there are 20 combat aircraft. But with Harriers flying in pairs, one designating a target and the other firing, that bring the total number of RAF "guns" down to 14.

Then there is Nato leaders' reluctance to use Tornadoes. Specialists in low-level, high-risk bombing runs they have trained long and hard over the mountains of Wales and the Lake District. But the very nature of their skill puts them at risk from Serb air defences - a risk Nato does not want to run.

Technology costs

Technical difficulties have also dogged the RAF. Paveway II and III "smart" bombs may have worked well in the clear skies of Iraq but in the bad weather of spring-time Yugoslavia they have hampered pilots anxious to avoid collateral damage.

American pilots have access to even "smarter" bombs such as the JDAM (satellite guided and unaffected by weather) and this partly accounts for the US air force's greater strike rate.

The Treasury has agree to fork out for these sophisticated and expensive weapons but they will not arrive for some time.

Army cuts

The Strategic Defence Review plans for two brigade-sized operations running concurrently, or one divisional size operation - such as the Gulf War contingent - at any one time.

In fact there are already two brigade-sized operations in force - in Bosnia and Macedonia (not counting Northern Ireland). But a Ministry of Defence spokesman told BBC News Online they were planning for the future:

"We also have operational contingencies in place and our planning side is in close touch with our foreign policy side."

But with the SDR still two years away from completion, the Army has been caught at a bad time, having to meet Kosovo commitments while in the middle of reorganisation.

But as Ian Kemp, news editor of Jane's Defence Weekly, points out, overall the Army should come out OK, and restructured to deal more easily with operations such as Kosovo.

"As it stands now, the army is under strength, particularly because of the reduction in the Territorial Army. But the planned changes under the SDR will make it much easier to cope with the demands in a year's time."

Why us?

The issue then, says Ian Kemp, "is not can the UK cope with another major event on top of what it is handling, but why is the UK bearing a disproportionate share of commitment to international forces."

Alongside the US, the UK is consistently the largest troop contributor internationally - but that is a political decision and is beginning to change.

"Other forces within Europe, such as France, the Netherlands and Belgium are moving towards a British force model which will mean they will be much better prepared to contribute on the international scene.