There is a lot of fuss in the media about the new measures proposed by the government to monitor telephone calls and web access, and quite right too. But there is nothing new about this. Until now the UK has been quite happy to record similar information outside the UK where they were able to get hold of it. No UK laws against that. And they were fairly passive about the US listening in to the calls of UK citizens, in the hope/expectation that the US would share the juicier bits with the UK (and vice versa).
So now the UK is simply trying to do to its own people what the US and others may have been doing for some time. I am not an expert in what actually happens, but several years ago I met regularly on business with people from a state that has not been on the friendliest terms with most western countries. i was dealing with very substantial businessmen in that country, with very close ties to the leadership, met with senior employees of state companies and on a few occasions had meetings with ministers.
And this is what I was advised by someone who was very knowledgeable about the surveillance undertaken at the time: Throw away your mobile phone, or don't let anyone you meet know your mobile phone number. If any surveillance target calls you, you will go on a suspect list, likewise if you call them back. Don't take your mobile phone to meetings even if you don't use it because your position and the position of the "target" can be matched by time and place. Do it once and it might be a coincidence. Do it twice and the link is obvious. At the time you wouldn't be dealing with the UK authorities, but your entry into the US might have become difficult.
Worth remembering if this law goes through.