Richard Barrett, the former head of counter-terrorism at MI6, has told ITV News that despite today's new airport security measures, the US has a "hell of a task" keeping track of would-be terror attackers.
He said that while Britain may be considered a "softer target" for any terror group with global aspirations, the threat to the UK is not much smaller than it is to the US, and in many ways it is "easier to attack Britain".
More top news
The woman is described as being around 50 years old with short spikey purple hair.
No one gave him a chance - but Donald Trump has just pulled off one of the greatest feats in modern American political history.
German police are investigating an online picture thought to be of two British men doing a Nazi salute at a former concentration camp.