ANGRY war veterans will today ignore a plea from Tony Blair by staging a highly-public protest against the Japanese Emperor over Japan's mistreatment of British prisoners during the war.

Last night around 20 camp survivors held a protest vigil outside the Japanese Embassy in London as Emperor Akihito arrived at the start of his state visit.

The former PoWs, holding candles and Union flags, held a minute's silence at the start of the vigil in memory of the 13,433 Britons who died in captivity and the many thousands more whose lives were blighted by their ordeal.

Today hundreds of ex-Servicemen plan to turn their backs on Emperor Akihito as he travels down The Mall in London with the Queen in a horse-drawn, open-topped carriage.

Uniformed former prisoners of war may also whistle Colonel Bogey, the British wartime anthem made famous in the film The Bridge on the River Kwai, to show their disrespect.

They have decided to mount the protest, intended to highlight Japan's alleged failure to properly atone for torturing detainees, despite a request yesterday from the Prime Minister for Britain to give the Japanese head of state ''a warm welcome''.

Mr Blair urged the ex-PoWs to stop living in the past, accept Japan's previous apologies and recognise that an ex-enemy was now one of Britain's closest allies. However they will today take full advantage of what they see as a perfect opportunity to draw attention to their demands that Japan offers a full apology and compensation.

The veterans want Japan to meet their demands in order to lay to rest finally the lingering legacy of bitterness surrounding the torture, starvation and slave labour which British detainees were forced to endure in Japanese PoW camps for three years during the Second World War.

Mr Blair is worried that the action could prove acutely embarrassing and damage Britain's highly-profitable trade with links Japan, which is the country's third largest export destination after the European Union and United States.

In the statement yesterday about the planned protest, Downing Street took the unusual step of pointing out that British exports to Japan were worth #4200m a year, that Britain had secured more than 40% of Japanese foreign investment in the EC and that 20,000 jobs in Britain depended on Japanese firms.

That led to claims from veterans that the Government was more interested in maintaining trade links than righting a wrong done many years ago.

Downing Street said: ''The Prime Minister wants Britain to give a warm welcome to the Japanese Emperor. He sees this visit as an opportunity to celebrate a strong and modern relationship between former enemies who are now close allies on so many issues.''

The statement continued: ''Tony Blair believes that to allow our relationship to be defined solely by the past is to fail to understand fully the achievement of those who fought for freedom. He believes it's thanks to their sacrifice that Japan today is a very different country - democratic and with a commitment to peace.''

It emphasised that British-Japanese relations were at an all-time high and that Mr Blair wanted the Emperor's visit to be a success.

However, war veterans are planning to stage a protest at every event Emperor Akihito attends during his stay in Britain this week, during which time he will receive the Order of the Garter from the Queen.

Ex-PoWs held a protest vigil outside the Japanese embassy in London last night. They intend to deliver a letter to the Emperor this afternoon at Buckingham Palace, where he is staying, asking him to plead with the Japanese government to accept the calls for a full apology and fitting compensation.

Although various Japanese prime ministers have previously signalled their regret for what happened during the war, most recently earlier this year, the words themselves have fallen short of what veterans' leaders want to hear.

They yesterday rejected Japanese explanations that Akihito could not comment on the issue because the country's constitution forbids the Emperor from making political statements.

The Japanese Labour Camps Survivors Association and Association of British Civilian Internees Far East Region are locked in a legal battle with the Japanese government in a Tokyo court trying to get #13,580-a-head in compensation for all those who suffered.

Japan's only payments to British ex-PoWs came after the 1951 peace treaty, but the sums involved were just #76.50 for ex-POWs and #49 for internees.

Veterans' leaders claim they have found new evidence which will force the Toyko government to pay much more.

Mr Martyn Day, the solicitor acting for the veterans, called on the Prime Minister and the Foreign Office to now ''take up the cudgels'' on the ex-servicemen's behalf.

Mr William Holtham, a former worker on the infamous Burma Railway - subject of the film Bridge on the River Kwai, said: ''I came home with very bitter memories of the Japs. We were nothing but slaves - we had to do their bidding on pain of death.''