Eben Kirksey and Jack Grimston – Britain's biggest company, BP, has angered human rights groups by becoming involved with Indonesia's brutal security forces in an attempt to protect a 1 billion Pound gas production scheme.

The company is using officers from the country's feared Mobile Police Brigade (Brimob) – which has been accused of numerous human rights abuses – to guard explosives at the Tangguh project in the province of West Papua, which is due to begin production in 2007. Earlier this month the company also held a seminar in Jakarta with army and police commanders to discuss the level of protection that they would give the project.

Indonesian security forces have been condemned by Amnesty International for torture, extra-judicial executions and "disappearances" in West Papua. Thousands of people have been killed in the conflict over the past 40 years. The company claims that a new "community-based" security policy will help it to gain the trust of local inhabitants, minimising the chance of violence breaking out and provoking full-scale intervention by the military.

Human rights groups, however, believe the policy has little chance of working in West Papua. Lucia Withers, Indonesia researcher for Amnesty, said: "Can BP really provide security? The situation is fundamentally unstable and you have a wild card in the form of a very powerful and almost totally unaccountable military."

The allegations over Tangguh threaten BP with similar embarrassment to that caused by its investment in Colombia, when it was criticised for links to an army accused of collaborating with paramilitary death squads.

In its 100 million Pound relaunch in 2000, BP used the slogan "beyond petroleum" to re-brand itself as an ethically and environmentally responsible company. Its policy states: "We must work to ensure that our actions do not negatively impact human rights."

BP's activities in Indonesia may also cause political problems in Britain, where the company has close links with new Labour. It employs several former aides of Tony Blair, including Anji Hunter, a former special adviser. Lord Browne, BP's chief executive, is a Labour peer.

West Papua is the size of France but has a population of only 1.7 million. It contains the world's second largest rainforest and has vast mineral resources, including gold, as well as gas reserves. In contrast to well-armed guerrillas in other parts of the world, many of West Papua's rebels wield only bows and arrows.

The security forces have been accused of using nationalist movements all over Indonesia as a pretext for obtaining "protection" money from companies. Some 80% of the army's revenue is believed to come from these sources. BP's community policy aims to avoid this by relying largely on locally recruited security guards – 65 have already been trained – to keep the army presence to a minimum.

But human rights groups believe the temptation of Tangguh, likely to become one of Indonesia's biggest foreign currency earners, may be too difficult for the army to resist. The company training the new guards, however, is run by Harianto, a former brigadier general in the Indonesian marines.

Some critics believe the army may have already staged violent incidents as a pretext for intervention. One occurred in 2001, when five police officers were killed. After the shootings, Brimob launched an operation, called Sweep and Crush, in which they executed or tortured to death at least eight people. However, Barnabas Mawen, a pseudonym for one of the group which killed the policemen, told The Sunday Times that Indonesian military agents had supplied him with bullets, food and money before the attack.

BP said its security policy was designed to minimise the likelihood of military involvement. "BP's goal is to create a security system based on understanding and consent where responsibilities are clearly defined," said a spokesman. "The Indonesian security forces will have a very constructive role. exactly what size and presence of the Indonesian security forces will be involved will be for them to determine."