A group of Gurkhas from Nepal have handed in a petition to Downing Street to demand the same pay and pension rights as British-born soldiers.
The veterans are calling on the Queen to change their pensions
The veterans say many ex-Gurkhas have been left "destitute and disillusioned" by unequal pensions.
About 30 Gurkhas marched to No 10 before handing in their petition.
The government says members of the Gurkha Brigade do not need as much money because the cost of living in Nepal is lower than in the UK.
Pensions for serving Gurkhas have been reformed for those who left the service after 1 July 1997.
In a speech outside Downing Street, Capt Rambahadur Limbu, 70, a Victoria Cross winner, said: "It is an honour for me to be once again in England.
"But I come because we have some problems and it is high time that these problems are addressed by the concerned authorities in London."
The 1 July 1997 cut-off date was a "great concern", he said.
"The Gurkha veterans with no pension is also a serious issue," he added.
He called on the government and the Queen to "deal with the injustice faced by the Gurkhas".
Falklands veteran Sgt Deepak Maskey says he receives a pension of £130 per month, but that a British comrade would get more then £600.
There were 32,000 Gurkha veterans living in Nepal who had been affected by the cut-off date, he added.
"We have been with the British soldiers throughout every major war," he told BBC News.
"Now people begin to realise in this 21st century that there have been discriminations and we want to break that."
The British government's argument that it was cheaper to live in Nepal was "totally irrelevant in the pension issue", he said.
"Would [UN Secretary General] Kofi Annan be paid pensions based on the cost of living in Ghana? Certainly not," he said.
A Ministry of Defence spokesman said Gurkha conditions of service had been "determined not to be discriminatory but rather appropriate to their unique status as Nepalese citizens serving in the British Army".
Their "unique pension arrangements" had been vindicated by a judicial review in 2003, she added.
"Gurkha service pensions, paid under the Gurkha pension scheme, compare favourably with professional and white collar salaries in Nepal."