The definition of threat levesl depnds on who you ask -
the old advice to "never ask a barber if you need a haircut" applies
Each service adds its own threats which funnily all seem to require their branch to be refitted, the FO adds a load as they don't want anyone coming along in 25 years and spiling their retirement with a "Guilty Men" scenario
the Treasury can't see any threats and therefore we don't need to spend anything etc etc
personally I think we in the UK are faced with fewer serious threats than at any time in my lifetime - most of the ones that people list are either fights far away we decided to pick or fights (such as India-Pakistan) we don't need to get involved in
We still need armed forces but they have to be configuired for max flexibility - eg more helicopters and transports and a lot of cheapish strike fighters, more amphib. vessels rather than the big carriers, a decent infantry transport vehicle for once. More infantry and less tanks