« Reply #4 on: Wednesday 14 February 18 01:10 GMT (UK) »
Have you found his medal card and noted the date he signed on? My grandfather and three of his brothers in law were in the Northumberland fusiliers and they lived many miles away in the old East Riding of Yorkshire. I was fortunate to find the WWI medal cards of all four men which showed they belonged to the RAMC (Royal Army Medical Corps) and three of them had consecutive army regiment numbers dating from 1911. Another piece of good luck was that my grandfather's complete records from 1911 to his discharge from the army in 1916 (from exposure to gas poison) were all intact.
In 1908, the government of the day had decided to recruit a part time Territorial army which they could call on if and when the country needed them - and from the list of battalions in the Northumberland Fusiliers, their recruiting office had been very busy
The records show that my grandfather trained in his home town but spent a couple of weeks up in Newcastle, Northumberland, for additional specialist training. The 1911 census show he and his brothers in law were all poorly paid unskilled workers and I imagine that they earned extra money doing a few hours per week in the local territorial army - maybe a couple of hours midweek and a few more hours on a weekend - just like the territorial army of today.
This page shows the Regiments of the London Borough which doesn't include the Northumberland Fusiliers and it may be that his original battalion was eventually amalgamated with the NF when the need arose.
https://en.wikipedia.org/wiki/London_Regiment_(1908-1938)
Aberdeen: Findlay-Shirras,McCarthy: MidLothian: Mason,Telford,Darling,Cruikshanks,Bennett,Sime, Bell: Lanarks:Crum, Brown, MacKenzie,Cameron, Glen, Millar; Ross: Urray:Mackenzie: Moray: Findlay; Marshall/Marischell: Perthshire: Brown Ferguson: Wales: McCarthy, Thomas: England: Almond, Askin, Dodson, Well(es). Harrison, Maw, McCarthy, Munford, Pye, Shearing, Smith, Smythe, Speight, Strike, Wallis/Wallace, Ward, Wells;Germany: Flamme,Ehlers, Bielstein, Germer, Mohlm, Reupke