Government guidelines are allowing British companies to export arms equipment to countries where they could be used for repression and human rights abuses, campaigners have warned.

A report published by Oxfam, Amnesty International and IANSA said that ministers are applying weaker controls to the export of components, compared to the export of full weapons systems.

"These double standards allow British-sold weapons components to end up in countries where they could ultimately be used to violate human rights," the campaigners said.

An analysis contained in the report revealed that since 1998 there has been an eleven-fold increase in the number of arms components licensed for export.

The government has refused repeated requests to release the total number of all components sold to each country, said the report.

Loophole

But the loophole has allowed British arms components to be sold to a list of countries including Zimbabwe, Israel, Indonesia, Colombia, Nepal and the Philippines.

"These aren't simply nuts and bolts we're selling, these components include firing mechanisms, bomb making equipment, guidance systems and gun barrels," said Justin Forsyth of Oxfam.

"It is these deadly components that are key parts of full weapons, without which they would be unusable."

Lesley Warner of Amnesty International added: "Components for deadly weapons are being sold to known human rights abusers.

"It doesn't take much to re-assemble them. And from there it takes even less to kill, to torture or to rape at gunpoint. This loophole must be closed immediately."

The campaigners also said that a change to the rules introduced by foreign secretary Jack Straw in 2002 meant that rather than solely basing decisions on export arms components on human rights, conflict and poverty considerations, new criteria were introduced to assess potential deals against their importance for the arms industry.

Since the decision, the number of arms components licensed for export has doubled.