Unfortunately there is not a simple answer. There’s no way to block GCHQ surveillance completely. Even if you rebelled against technology, ditched your mobile phone, and avoided using heavily-tracked web services like Facebook and Google, you’d still be on surveillance cameras that capture your face, license plate scanners, and credit databases, among other things. But let’s not get pessimistic. There are tools you can use to make it harder for others to track you. They won’t eliminate your footprint, but they’ll blur the picture of you that emerges through your data.