By Finlo Rohrer BBC News Online

Foreign workers and tourists have often been easy targets for rebels seeking ransoms or political leverage in their struggle for a Marxist state within a state.

Aberdeen oil worker Alistair Taylor spent a harrowing two years in the jungle after being captured by fighters thought to be with the Marxist National Liberation Army or ELN.

He told BBC News Online the captives, who include two Britons, would face the most frightening part of their ordeal now as the rebels moved between hiding places in order to evade capture.

Tom Hart Dyke and Paul Winder returned safe and well

"It is not the kind of place you go on holiday to go walking about. If you go into country like that you have to be aware.

"They will be marched, they won't get a minute's rest.

"The guerrillas are going to be as scared as them. They need to get them hidden, the army is looking for them. They will be under a lot of pressure, keeping them moving.

"I was in different circumstances. This might be just that they walked into the wrong place at the wrong moment, an opportunistic act.

"They will probably have been running between camps and stations. They wouldn't be looking to stop and eat."

If they have got basic Spanish, they won't understand the mountain Spanish Alistair Taylor Former hostage

Mr Taylor said it had taken him a long time to return to normal life after his release in the summer of 2001, although he was now in good health.

"How long it takes to recover depends on your mental strength."

He said he had concealed his good grasp of Spanish - gained from working in South America and marriage to a Colombian - from his captors for nine months in order to glean information.

But he said tourists with a smattering of Spanish could suffer.

"If they have got basic Spanish, they won't understand the mountain Spanish."

Mr Taylor said the moment the hostages would dread most would be if government forces caught up with the rebels and attempted to free the hostages using force.

The Foreign Office warns against all travel to the provinces of Choco, Putumayo, Meta and Caqueta and to rural areas of Antioquia, Cauca, Narino and Norte de Santander.

Alistair Taylor hid his fluent Spanish from captors

The Sierra Nevada where the tourists were kidnapped is not specifically included in the advice, but any travel outside cities is dangerous.

"Overland travel in Colombia is not the way to go, you should really fly. There have been a number of kidnappings.

"We advise against any travel to areas where there is guerrilla activity or coca growing."

Former merchant banker Paul Winder said he and orchid expert Tom Hart Dyke had made an error of judgement when they were captured in the hazardous Darien Gap area on the border with Panama.

The pair were held for nine months before being released and trekking out of the jungle.

Mr Winder said it was still perfectly safe to visit many parts of Colombia, but tourists would be making a grave mistake in venturing off the beaten track.

"If you go outside certain areas there is a good chance you will run into trouble. It is a bit hairy in Colombia, kidnapping is pretty much the national sport over there.

"But what we did was take an unjustifiable risk. I would never go into a region like the Darien Gap again."

The situation for the kidnap victims would be particularly chaotic in the first few days, Mr Winder said.

"There will be utter confusion. For a couple of weeks they just marched us round. They will be trying to ascertain whether you are worth anything.

"We were always trying to give them as little information as possible. Initially they wanted $10m."

Tropical worms

Despite violence and death threats from some of the rebels, Mr Winder said he and his fellow captive had got on with most of them.

"We taught them cricket, they had trouble with LBW. We played cards, I had a chess set.

"In fact, our major problem was putting up with the jungle conditions. You can get infections, I got a problem with my leg caused by tropical worms. I've got a permanent scar."

He added: "Every one of them has the usual ubiquitous AK-47, light machine guns and so on, and they carry that weapon with them wherever they go.

"The best thing to do is to remain calm. don't antagonise them. The biggest fear is not knowing what's going to happen."