Tony Blair reckons that the UK's interventionist foreign policy is justified. Well if he really believes that, then he's a fool...
The head of Her Majesty's Government is misguided for a number of reasons. Firstly, the United Kingdom isn't a superpower. We have no real right to aid in "policing" the world (OK, one can ask whether any superpower has the right or duty to police the world, but that's another argument..) The days of Empire have gone and people should realise that Britain is relatively less powerful than it used to be.
Secondly, this foreign intervention makes us a target for terrorists. And no, I don't believe the Islamists "hate our freedom/way of life". If you were a Muslim living in the Middle East, how would you feel if Western powers were always intervening in your region's affairs? The USA, for one, not only invaded Iraq, but supports the House of Saud, supports Israel, initially helped Saddam, has threatened Iran, etc. Don't forget that Muslims share a sense of "brotherhood" with other Muslims and would care if some members of Islam are being persecuted. Islamists have realised that enough is enough and are fighting back.
If Islamists truly do hate our freedom, then why have only a few Western liberal democracies been attacked? Why hasn't France, Germany, Italy, Sweden, etc. been aggressed against? Also, the UK was a freer place in the 19th century. It was also the age of Empire and we were intervening in many parts of the world. Why was there no Islamist terrorism then? A terrorist attack would have been easier to execute in that day and age.
Our armed forces should be focused upon national defence, not national offence. Many hotspots around the world have no direct bearing on our national sovereignty. Did Iraq, or Sierra Leone, or Afghanistan or Kosovo?