Said it once, I'll say it again; The UK armed forces are a paper tiger.
All in all, they're woefully understaffed for suppressing any kind of large scale civil disorder here and the lack of up to date equipment is just the tip of the iceberg. There are literally only 150,000 service personnel across all 3 branches, much of whom are support staff. For context, London alone is a city of 9,000,000 people. If a situation emerged where 1/10 Londoners rioted, such as, say, if their gas and electric became too expensive and they were freezing in their homes, then the entire UK armed forces and police would be outnumbered by a factor of 3-1. All in just one city. Out of 75 scattered all across Great Britain.
This doesn't even take into account that much of those armed forces are stationed abroad in the ~145 British overseas military installations all over the world, particularly those in Germany and Cyprus.