The flashbulbs would have been enough to startle anyone.

But the 13 Britons who emerged into the glare of the world's media after eight days trapped below ground, followed by the threat of indefinite detention in Mexico, took the attention in their stride.

Retired Army major Jonathan Sims, 41, of Brighton Road, Lancing, spoke of his ordeal after arriving home yesterday.

He was among a group of 13 British potholers expelled by the Mexican authorities, who accused them of violating their tourist visas and making false statements about the purpose of their visit.

Mr Sims and six of his fellow cavers had spent more than a week underground before they were rescued from flooded caves - only to be detained over allegations which sparked a diplomatic row between Mexico and Britain.

Mr Sims said he and his colleagues had been made to endure sleep deprivation at the hands of Mexican officials.

He said one night they were woken up twice, once by a man banging a hammer and changing locks on a door and again to be told they had to move to another department in the morning.

He said: "It was completely unreasonable and it was obviously done with the intention of depriving us of sleep but I think that was just one specific individual."

Mr Sims said he did not think it was representative of how people were treated in Mexico in general but he said: "We're all cavers.

"We kind of deprive ourselves of sleep routinely but we actually don't like it when somebody else does it for us."

Mr Sims said the party had received a number of apologies from officials for the way in which they were being treated.

A plane carrying the cavers home touched down at Heathrow shortly after 2pm yesterday.

The other detainees were RAF sergeant John Roe, in his late 30s, Warrant Officer Charles Milton, 47, Army sergeant Chris Mitchell, in his late 30s, Captain Toby Hamnett and civilian guide Simon Cornhill, 36.

Only when they emerged from the depths of the caves into the flashing lights of the world's media did they realise the extent to which their expedition had been broadcast across the world.

The leader of the group, Major Stephen Whitlock, remained above ground during the rescue and insisted they had done nothing to violate their tourist visas.

Major Whitlock said at Heathrow: "The only thing that we were doing in Mexico was enjoying the sport of caving, finding new caves where nobody has ever been before."

Warrant Officer Milton said he was looking forward to tucking into a full English breakfast when he returned home.

The six potholers became trapped by rising flood waters in caves at Cuetzalan, north-east of Mexico City. They were rescued by a team of British divers on Thursday.

After that ordeal the six, along with seven other team members, were held in an immigration detention centre for five days before being expelled.

Major Whitlock read a statement outlining the events surrounding their ordeal.

He said the rescue was "part of a contingency plan developed in the United Kingdom well before our departure."

He said the operation could not have been performed without the assistance of British divers.

He defended the team's decision not to make use of local expertise during the rescue, saying: "We were offered help from the Mexican authorities and from Mexican cavers which we used during the rescue.

"When we were offered help from the divers that wasn't a problem but when we actually showed them the cave we showed them the complexity of the operation involved and they didn't believe they could help us.

"Certainly the special forces colonel who was offering that help agreed we were in a better position to use cave divers from the UK who had actually practised this operation rather than sending in guides who hadn't been familiar with the cave."

Mexican president Vincente Fox reacted with fury to the group's refusal of help from local experts.

Armando Salinas, the country's assistant interior secretary, claimed they did not say they were undertaking a cave exploration expedition, for which they would have needed a different visa, or that they were military personnel.

Foreign military exercises are forbidden on Mexican soil.

The Mexican attorney general's office found no evidence the cavers acted illegally following an investigation into reports that they were looking for uranium.

Mr Sims said: "We got the impression there was some hidden agenda higher up driving our detention and even though they couldn't find anything at all that we had done wrong they were for some reason reluctant to release us.

"I asked the Mexican authorities why they had to search our bags again and again but each different department in Mexico did not want to accept what the others had said.

"We think there may have been an internal problem they wanted to mask."

He also said there were human rights issues surrounding their treatment in jail.

Mr Sims appeared relaxed and in good spirits as he spoke and sported an Indiana Jones-style hat.

He carried a pack of cards, which he said was the only entertainment the group had during their underground ordeal.

The expert diver, dubbed "Indiana Sims" by colleagues because of his regular daring escapades, said the group's treatment was unreasonable.

He said: "It was done with the intention of depriving us of sleep but that was not representative of the way we were treated in general."

Mr Sims retired from the Army three years ago.

He was chairman of the Combined Services Caving Association and the most experienced caver in the party.

His parents said the hobby was his life.

His father Allan, of the same address in Lancing, likened his son's ordeal to the treatment of a group of plane spotters who were held on spying charges in Greece two years ago.

He said: "It was much ado about nothing. They didn't let anyone know at first because they were never in danger.

"Jonathan could not understand what the fuss was about."

Major Whitlock thanked the Mexican authorities and the people of Cuetzalan for their assistance.

He said their detention had been fair "on the whole" but the group had made several complaints to the human rights authorities in Mexico which are currently under investigation.