Stuk,
Labour have promised an 'above inflation increase'. However small. The Tories have promised only to maintain spending at its current level for two years, without any inflation-pacing.
Defence isn't safe in any politician's hands - it doesn't swing enough votes and is not a priority. It would be foolish to see the Tories (on their record) as being any better than the present lot on defence, and in fact, for all the nonsense in other areas, I do think Labour have done a better job on defence spending than I'd have expected, with SDR being far less swingeing than anyone dared hope.
The Lib Dems are the real enemy to defence spending!