Mr Patch returned to Passchendaele in 2007 for the 90th anniversary of the battle, laying a wreath, not only on a memorial for the British dead, but also at a cemetery for the German victims of the offensive. On his 101st birthday he travelled to France where he was awarded the Legion d'Honneur, and subsequently made an officer of the Legion d'Honneur. In 2008, he was also honoured by the Belgian king, Albert II, who appointed him Knight of the Order of Leopold.
Patch had no time for the Act of Remembrance on 11 November, an event he described as "just show business". He always maintained that his Remembrance Day was 22 September, the day he lost his three best mates and his war ended.
Prime Minister Gordon Brown said: "I had the honour of meeting Harry, and I share his family's grief at the passing of a great man: "I know that the whole nation will unite today to honour the memory, and to take pride in the generation that fought the Great War. The noblest of all the generations has left us, but they will never be forgotten."
A national memorial service should be held as "a special commemoration" of the efforts of Mr Patch and "a generation of people" who fought in World War I, Mr Brown added.
The Ministry of Defence said there would be a funeral cortege through Wells followed by a service at Wells Cathedral.