Rupert was born in 1898, the son of William Wilson Horn, a Patent Trade Mark Agent [1911 census], and Sarah Amelia (nee Barker). He married Annie Winifred Knight on the 8 Dec 1917 at St. Stephen's Mission Church, Putney. His occupation on the marriage certificate was  Motor Salesman. He died on the 16 May 1970.  There is more information on Rupert Horn on the website of his great grandson Rob Curran at :-  https://adnepos.wordpress.com/horn/rupert-william-horn/ My thanks to Rob for the attached photo

Service record - 13th Bn. (Kensington) London Regt. (note these papers are in the Pension records)

Served - 6 Aug 1914 to 10 Aug 1914 (5 days), No.1798
Apparent age on medical - 17yrs 6mth.
Address - 5 Westmorland Rd, Barnes.
Next of Kin - father, Wm Horn, same address.

Service record - 25th London Bn.

Enlisted - 31 Aug 1914, citing previous service with the 13th Kensington.
Served - 2/25th C. of L. Cyc. reserve, no.1730, from 31 Aug 1914 to 30 May 1915.
Address - 5 Westmorland Rd, Barnes.
Age - 18 yrs 1mth (on 31 Aug 1914) Note -  he was born in 1898, and really only 16 yrs old.
Next of Kin - father, Wm Horn, same address.
Discharged in consequence of enlistment in A.S.C.M.T. - no. M2/101580.

Service record - Army Service Corps.

Enlisted 4 Jun 1915, citing previous service with the 2/25th Londons.
Address - 5 Westmorland Rd, Barnes.
Age - 19yrs (see comment above).
Occupation - Motor Driver
Next of Kin - father, William Wilson Horn, same address.
Served in France from 18 Sep 1915 to 11 May 1916.
Discharged - No longer medically fit for service.

[My thanks to Russell Ridout for the above photos.]