Former prisoners of war in Britain will on Thursday take their protest to the gates of Downing Street and deliver a letter to the prime minister before a visit by Emperor Akihito.
It will be their fourth protest in three days as they continue to haunt the emperor during his visit.
On Wednesday, Emperor Akihito managed to keep his composure as he was dogged by protesters during his visit to Wales.
Former POWs also turned up later in the day as the emperor and his wife attended a white-tie dinner in London's financial district hosted by the Lord Mayor of London.
The shouts of about 30 former civilian prisoners could be heard over the bagpipers welcoming the Emperor and Empress to London's Guildhall on Wednesday night.
But once again, Emperor Akihito took the demonstrators in stride, continuing with his official duties, including inspecting the honour guard stationed outside Guildhall.
It was the second day of protests over Akihito's state visit to the U-K, a visit which was at the invitation of Queen Elizabeth II.
His trip has angered former prisoners of war in Britain, who are demanding a formal apology for Japan's treatment of them in the Second World War.
But the host of the Guildhall banquet - London's Lord Mayor, Alderman Richard Nichols - assured his Japanese guests that they were very welcome.
He added that Britain and Japan both wished to see a stable climate for investment.
"Our countries have common interests and aspirations and we both wish to see a stable and prosperous world where investment in free trade and industrial services and products thrive."
SUPER CAPTION: London's Lord Mayor, Alderman Richard Nichols
At a Buckingham Palace banquet on Tuesday, Akihito had alluded to the protests, saying he and the empress could never forget the suffering of so many people during the war.
During his speech at Guildhall 24 hours later, he said he hoped his visit would bring Britain and Japan closer together.
"The relationship between the two countries has developed into something important, not just in the economy or finance, but both countries can make contributions to each other. It is a development that I could not have expected during my first visit."
SUPER CAPTION: Emperor Akihito
Japan's Kyodo News Agency has quoted Prime Minister Ryutaro Hashimoto as saying that the emperor has done his best to express his own thoughts frankly without getting involved in politics.
Hashimoto reportedly added that he hoped the Emperor's feelings would be accepted by the British people.
But that hasn't been the case.
Earlier on Wednesday, dozens of former prisoners-of-war turned their backs on Akihito as he arrived in Wales, the main centre of Japan's massive investment in Britain.
The POWs have vowed to protest for the duration of the Emperor's stay in Britain.
Later on Thursday, they will take their protest to 10, Downing Street where they will hand a letter to Prime Minister Tony Blair.
The protesters have rejected his attempts at reconciliation.
"Tony Blair said yesterday give him a warm welcome. I think he must be out of his tiny mind."
SUPER CAPTION: Former P-O-W
The emperor is due to attend a reception and lunch hosted by the prime minister at Downing Street on Thursday.
The POWs have promised they'll be there to continue their campaign for an apology from Akihito and compensation from the Japanese government.