A news article says the following:
There are 18 control orders in place against terrorism suspects. These are powers that severely restrict the movements of alleged terrorism suspects who have not been charged with a crime.
Critics say it amounts to house arrest. Two of those subjected to control orders have absconded along with a third man who had been due to be served with an order.
Prime Minister Tony Blair has described allegations that Britain has become a police state as a "gross caricature".1
To control people indefinitely in home detention without having convicted them in a proper court of law is a Police State action. Tony Blair doesn't want to admit that the UK has crossed the line. The UK is behaving as a police state; therefore, it is a police state.
Of course there are relative degrees. The UK hasn't reached the level of Stalinist Russia or Hitlerian Germany, but it is most definitely trending in that direction.