Royal British Legion
The Royal British Legion (aka TRBL, aka 'The Legion') was formed in 1921 to offer cut price alcoholic fluids to servicemen of World War One through a network of social clubs. Today, they afford an ideal forum for anyone associated with the military to pontificate about how the services were “better in their day” - much like ARRSE.
In addition, they also provide a significant amount of financial and emotional support to the 10.5 million eligible people in the UK. On a yearly basis they deal with thousands of cases, safeguarding the welfare, interests and memory of all serving and ex-serviceman. They provide a potent voice for their community (e.g. the recent 'Honour the Covenant' campaign) and are nationally recognised through their Poppy Appeal.
There has been much discussion of late surrounding the Poppy Appeal, and whether or not it's losing its core focus with the huge increase in merchandise and poppy styles, however it's all fairly academic as you either give a damn or you don't.
You'll often see an old and bold stood at the entrance to a major train station or shopping centre, eyeing up the diverse racial mix and thinking back to the good old days when he was bayonet charging their type in Aiden or Malaysia. Or as my grandad, after too many stouts, once said in a restaurant where he was served by a Burmese lad "I probably killed your grandad!"
The RBL is always on duty.