Colombia is running a slick tourist campaign promoting the country as a safe destination but armed conflict still plagues many rural areas. Cities such as Bogota, Cartagena and Medellin have become safe after a decade-long, US-backed military offensive that has pushed guerrillas deep into the jungle. Motorways are more secure, a far cry from the ambushes that once made bus journeys a lottery.

The problem is in remote areas where rival groups – leftist rebels and right-wing militias – continue waging a ruthless struggle for control of coca crops and cocaine trafficking routes.

Instead of pitched battles, massacres and burning villages, the four-decade-old war has morphed into a murky conflict of intimidation, extortion, spying and targeted killing.

"The guerrillas and paramilitaries still recruit youngsters but instead of taking them off to fight they leave them in the villages to keep an eye on what's going on," said sister María del Carmen, a nun in Bojayá, scene of a 2002 slaughter. Hundreds of thousands of displaced farmers have not returned home for fear of being caught in the middle. They do not trust the army to protect them and do not believe government claims to have disarmed and demobilised the militias.

Farc and ELN guerrillas do not appear to be targeting foreigners for kidnapping but step on one of the mines they lay and it does not matter what nationality you are.

There is no front line but insecurity threatens areas where coca is grown. The Parque Nacional Tayrona is in one such zone. The Foreign Office reckons it is OK as long as you stick to beaches and resorts but advises against venturing inland to sites such as the Lost City. "Illegal armed groups are active and drugs are grown and processed in the area," it warns.

Tourists have been going there without reported incident since treks resumed in 2005 so maybe it is safe. But nothing is guaranteed.