First of all they're links from wikipedia, but I see no reason why they shouldn't be reasonably accurate.
The UK apparently has the fifth largest GDP on the planet:
List of countries by GDP (nominal) - Wikipedia, the free encyclopedia
We also have the fifth largest defence expenditure:
List of countries by military expenditures - Wikipedia, the free encyclopedia
If our armed forces are becoming pitiful in size, when we spend more than for example France, Japan and India, and about 90% of Russia's military budget, then you have to ask whether we are getting value for money.
I read recently on a pprune thread, I can't remember which, that companies routinely put their prices up by 200-300% on MOD contracts.
If we were to get better value for the money we spend, we would have more credible armed forces.
Easy to identify the problem - more difficult to resolve it!!
Then again, there is the issue of armed forces being a priority. If UK political parties aren't interested in anything other than the sacred cows of NHS and education, then the defence budget will only get smaller....