The Ministry of Defence yesterday announced the doubling of lump-sum payments for permanently disabled veterans of Afghanistan and Iraq to £570,000, but capped the maximum amount at that figure and backdated it by only three years.

The Ministry of Defence yesterday announced the doubling of lump-sum payments for permanently disabled veterans of Afghanistan and Iraq to £570,000, but capped the maximum amount at that figure and backdated it by only three years.

Assessments for compensation will also still operate on a "tariff" system of placing a defined cash value on each of the three worst injuries to any individual to set the final compensation level.

It will not apply to anyone severely disabled during the invasion of Iraq in 2003 or during the violent insurgency which followed in 2004.

The new tax-free payout benefits about 80 injured soldiers in total, many of who have lost two or more limbs, suffered brain damage or been paralysed since the introduction of the existing tariff compensation scheme in 2005.

It follows sustained media and political campaigns to improve terms after the revelation that an RAF typist with repetitive strain injury received almost twice the compensation offered to servicemen crippled in action.

The maximum lump-sum payment for the worst injuries will rise from its current, and much-criticised £285,000, with guaranteed annual income for permanently disabled personnel rated on age, rank and salary. For the average infantry private that means £15,000 a year.

While welcoming the rise, critics questioned the need for the amount to be capped when those involved were men in their early 20s who could expect another 40 to 50 years of life needing constant care and expensive special facilities to help them cope with their disabilities.

Lawyers for Lance- Bombardier Ben Parkinson, who lost both legs and suffered brain damage in a landmine explosion in Afghanistan in 2006, said the improved terms did not go far enough.

Doctors described him as "the most severely wounded British soldier ever to survive after a landmine explosion". He suffered 37 separate injuries, including severe brain damage, memory and speech loss, multiple fractures and the amputation of both legs.

Solicitor Andrew Buckham said: "We do not believe there should be any upper limit on the compensation that soldiers are awarded. It should instead be assessed on each individual's injuries.

"To cap this payment will inevitably mean that the most seriously injured, including Lance-Bombardier Parkinson, will still not receive the full compensation they need to ensure their life-long care needs are met."

About 80 less seriously injured troops - most of them wounded in Afghanistan - will see improvements of up to 80% in their lump-sum payments.

Bryn Parry, co-founder and chairman of Help for Heroes, which supports servicemen and women wounded while serving their country, said: "Any increase in the compensation package is wonderful. As far as we are concerned they can never get enough."

The Royal British Legion said the deal was "a victory for servicemen" in the wake of its Honour the Covenant campaign calling on the government to fulfil its duty to those who make a "unique commitment" to their country.