Former Gurkhas are taking the Government to court claiming they have suffered racial discrimination, with pay and conditions worse than those of other British soldiers.
In a challenge that could cost the Ministry of Defence £2bn, lawyers will argue in 20 test cases that the Nepalese fighters serving with the British Army retired on inadequate pensions.
Their legal team, led by the Prime Minister's wife Cherie Booth QC, will lodge papers at the High Court in London on Wednesday next week.
The recruiting of Gurkhas into the British Army is regulated by a tripartite agreement between India, Nepal and the UK signed in 1947. It is argued that the agreement links the remuneration of Gurkhas, who have fought for the British for almost 200 years, to the Indian army's pay code, resulting in a disparity in salaries and pensions between the Gurkhas and other British troops.
Lawyers for the Gurkhas say that, as a result, more than 30,000 men retired from service without any pension, or adequate pension, and suffered dire poverty. They say many wives have not been fairly compensated for the loss of husbands due to military service.
Padam Gurung, president of the Gurkha Army Ex-Servicemen Association, said yesterday: "The Gurkhas have been loyal servants of the British for 196 years, and have lost between 50,000 and 60,000 lives.
"All we ask is not to be treated as inferior human beings and to suffer discrimination.
"We want recognition that we have fought loyally as British soldiers and demand only the same rights.
"We hope the UK Government will now listen to our case but we are not afraid to seek justice in the courts."
The applications will go before a judge within the next few weeks to decide whether the Gurkhas have an "arguable case" to justify a full application for judicial review.