Elite British troops have been demonstrating how they train in the Bernese Oberland in a bid to prove they are here as tourists and not soldiers.
Dressed in civilian clothes, the Royal Marines recently staged ice climbing and rescue exercises on a glacier near the Sustenpass to prove that the high-altitude adventure training they undertake in Switzerland has no sinister motive.
The demonstration was organised by the British Embassy in Bern after concerns were raised that allowing a foreign army to train in Switzerland could damage the image of Swiss neutrality.
Tourists not soldiers
The soldiers have been travelling ostensibly as tourists, without the knowledge of the Swiss defence minister, Samuel Schmid, or the army chief of staff.
But the British Embassy says the marines do not have to seek permission for such exercises in any of the countries they use for training.
Josef Leu, chairman of the British parliamentary defence committee, described the affair as "a storm in a teacup", while Swiss army sources told swissinfo that no rules or treaties had been breached, and that the soldiers could effectively be regarded as civilians on an adventure holiday.
Patrick Bangham, military attaché at the British Embassy, says the marines do not wear uniforms or carry arms while in Switzerland.
"They stay at ordinary campsites, guest houses or hotels, and actually contribute to the Swiss economy," he told swissinfo.
Controversy was further stirred when a former Royal Marines commander was quoted as saying that his soldiers were on the final stage of a nine-month training programme designed to improve their skills in mountain warfare.
But Major Paul Mattin, leader of one Swiss mountain expedition, denies this is the case.
"These are not special troops. These are standard Royal Marines and they're just training to a slightly higher level than they can elsewhere," he said.
"There is a link with military work - they could be called upon to move troops across mountains. But our training here is not solely tied to military engagement," he added.
Mattin does, however, admit that the glacial terrain is similar to the mountainous areas of Afghanistan, where he and four other officers now exercising in Switzerland were recently deployed.
History of Alpine adventure
British troops have been coming to the Swiss Alps for the last 25 years to give young soldiers training in scaling higher peaks and crossing glaciers.
A new team of 20 marines - including one US and two Dutch soldiers - recently arrived for a month of high-altitude training in Lauterbrunnen on an operation codenamed "Ice Flip".
"Nothing offers quite as much as we can achieve here in a month," says Heath Blewett, a British officer with fifteen years of experience.
"We'll be doing everything from climbing on rock and then moving into the higher ranges up to 4,000 metres, glacier travel, climbing on steep ice - really everything to do with Alpine movement," he adds.
Ordinary people may regard this sort of activity as the cruellest form of physical punishment. But for the Royal Marines, it's just like a holiday.
by Julie Hunt