Only the past 10, maybe 15 years - the worst damage has all been in the past 5 years - but you're right about it being both parties: under Labour we had RIPA and the wet-dreams of "Wacky Jacqui" Smith - which in turn enabled the the Tory gov's implementation of these regressive legislation.

The problem is how the UK cabinet is arranged and the politically powerful role of Home Secretary - where the job description is a license to dream up, campaign for, and implement the most effective means of "keeping the country safe". Quite unfortunate.

Long-term change would only be effected by having the role's description framed in the context of keeping the UK - and its freedoms - safe. It's a subtle change to the oath of office, but would hopefully prevent the recent abuses we've seen. Universal mass surveillance is fundamentally incompatible with our right to privacy.