[10] Henry is recorded in the 1901 census with his widowed mother Amy Jane Allingham (née Foster) (1873–1915), a laundry forewoman, living with her parents and brother at 23 Verulam Avenue, Walthamstow.

[13] Henry and his mother are recorded in the 1911 Census living at 21 Heyford Avenue, Lambeth, while his stepfather was lodging away from home working as a wheelwright.

[9] Allingham remembered seeing the City Imperial Volunteers return from the Second Boer War,[15] and also recalled watching W. G. Grace play cricket.

[16] On leaving school, Allingham started work as a trainee surgical instrument maker at St Bartholomew's Hospital.

[6] Allingham wanted to join the war effort in August 1914 as a despatch rider, but his critically ill mother managed to persuade him to stay at home and look after her.

He became formally rated as an Air Mechanic Second Class on 21 September 1915, and was posted to Chingford before completing his training at Sheerness, Kent.

The creation of the Royal Air Force did not initially have a big impact on Allingham and he later remarked that at that time he still considered himself a navy man.

Speaking with Dennis Goodwin of the First World War Veterans' Association, Allingham said, "It is a shock as well as a privilege to think that I am the only man alive from that original reorganisation when the RAF was formed.

[22] He started his longest stretch of employment in 1934 designing new car bodies for the Ford Motor Company at their Dagenham plant[23] which had opened only a few years previously in 1931.

He had lost touch with her in the 1970s following a family rift after the death of his wife in 1970; however she was still alive aged 88 when her father died, and living in Stroud, Gloucestershire.

[24] After Denis Goodwin of the First World War Veterans' Association tracked him down in 2001, a 105-year-old Allingham took a prominent role in telling his story so that later generations would not forget.

On 16 October 2003, he helped launch the 2003 Royal British Legion Poppy Appeal with model Nell McAndrew aboard the cruiser HMS Belfast.

[33] The group of RAF technical trainees that joined him at this ceremony continued to visit Allingham at his retirement home in Eastbourne.

At the same time, an exhibition was being planned for London's floating naval museum on board HMS Belfast, entitled the Ghosts of Jutland.

He did not attend the 2006 Remembrance Day parade on 11 November at the Cenotaph as he was in France at a wreath-laying ceremony and to receive the Freedom of The Town of Saint-Omer.

[35] On 18 April 2007 Allingham visited Wilnecote High School in Tamworth, Staffordshire to answer students' questions about the First World War, after they wrote to the few surviving veterans asking them about their experiences.

[5] On his 111th birthday in June 2007, a Royal Marines band played to Allingham on board HMS Victory before he returned with friends and relatives to the Queen's Hotel on the Portsmouth seafront for afternoon tea.

"[36] On 1 April 2008, the 90th anniversary of the establishment of the Royal Air Force, Allingham was a guest of honour at the celebratory events at RAF Odiham in Hampshire.

[38] In June 2008, as part of the National Veterans' Day celebrations, Allingham was given a guided tour of the Eurofighter Typhoon aircraft at BAE Systems in Warton, Lancashire.

[39] On 23 September 2008, Allingham launched a book about his life, co-written by Denis Goodwin, with an event at the RAF Club in London.

[40] On 11 November 2008, marking the 90th anniversary of the end of the First World War, together with Harry Patch and Bill Stone, Allingham laid a commemorative wreath for the Act of Remembrance at The Cenotaph in London.

He received a signed birthday card from First Sea Lord Sir Jonathon Band and saw a Mark 8 Royal Navy Lynx flying overhead while he was sitting outside in his wheelchair.

[50] The calls resulted in Her Majesty's Government approving on 27 June 2006 a National Memorial Service at Westminster Abbey to take place after the death of the last known British First World War veteran.

"[52] Allingham received a letter from Member of Parliament Tom Watson on 14 July 2006 explaining the reasoning for a national memorial service rather than a state funeral, as the intention is to commemorate the entire generation that fought in the war rather than single out an individual.

[53] In Harry Patch's book The Last Fighting Tommy, the author claims that Allingham planned to leave his body to medical science.

[55] However he was persuaded by Denis Goodwin to change his mind, as he became a symbol of World War I to remind people of the sacrifices made during the conflict.

[61] Allingham died of natural causes[62] in his sleep at 3:10 am on 18 July 2009 at his care home, Blind Veterans UK centre in Ovingdean near Brighton, aged 113 years and 42 days.

The service was preceded by a half-muffled quarter peal on the church's bells, rung by local ringers and members of the RAF and Royal Navy change ringing associations.

[69] The funeral was followed by a flypast of five replica First World War aircraft; British and French buglers played the Last Post and Reveille;[70] and a bell was tolled 113 times, once for each year of his life.