Hundreds of Afghan interpreters who served on the frontline with British forces in Afghanistan will be offered the chance of a new life in Britain after a government U-turn, it was revealed on Wednesday.

Prime Minister David Cameron had initially discouraged the interpreters from settling in Britain, saying "talented Afghans" should stay and rebuild their country.

But many of the interpreters say their lives are in danger from the Taliban due to their work with British forces in the restive southern Helmand Province.

The vast majority of British troops are due to withdraw at the end of 2014 along with other soldiers in the NATO-led international coalition.

Some 1,100 local Afghan staff work with British forces and government interests in Afghanistan, of which around 500 are interpreters, sources said.

It is believed at least 20 interpreters serving with British troops have been killed since 2001, while dozens have been wounded and a handful have been murdered while on leave.

Although details of the proposals have yet to be released, a government spokesman said "individuals who have regularly served outside the wire, alongside our troops on the frontline in Helmand" will be allowed to move to Britain with close family members on a five-year visa.

If they stay in Afghanistan, all local staff serving with British forces will be offered a training or education package and paid their salary for up to five years.

"These proposals give them a choice: the opportunity to go on working in Afghanistan, learning new skills and to go on rebuilding their country or to come and make a new start in Britain," a source in Cameron's Downing Street office said.

The British government is treating the offer as a "redundancy" package because local staff will be out of a job when British forces leave Afghanistan.

The decision came after three interpreters launched a legal challenge to press for the same treatment afforded to interpreters who worked with British forces during the Iraq war.

One of the Afghan interpreters, who wished to be identified only as Mohammad, said London had made "the right decision".

"Saving those people who have helped the British government is giving a message to the Taliban that the Afghan interpreters will not be left behind for them to be persecuted and hunted down by the terrorists," he told AFP.

Mohammad was forced to leave his wife and three children behind in Afghanistan after receiving death threats from the Taliban for his five years' work with British troops.

"I hope that with this decision now, I would be able to reunite with my family here in the UK and the other interpreters would be able to come here in the UK to live in peace with their family," he said.

His lawyer Rosa Curling, who lodged the interpreters' legal challenge at the High Court in London earlier this month, said she was "delighted" at the government's offer.

"While we await the full details of the scheme, we are delighted that the bravery of the Afghan interpreters now seems to have been recognised."

But she said she was concerned that some interpreters may not be eligible for the scheme if it was limited to those who had served on the frontline and not to others, such as Kabul-based spokesmen and those working for the intelligence services.

"Both groups remain at risk from threats from the Taliban and to refuse them access to the same resettlement options would be unacceptable," Curling said.

A government spokeswoman said Britain had a "mechanism" in place to support local Afghan staff concerned about their future safety. This was separate from the redundancy package.

"In the most extreme cases our 'intimidation policy' allows for relocation to the UK and this will remain in place," the spokeswoman said.

"This intimidation policy is separate from the redundancy package and will remain in place."