Heathrow has become the biggest airport in the world to allow passengers to carry two litres of liquids in their bags through security - just ahead of the half-term holidays. The airport has finally completed the rollout of new high-tech CT scanners. Electronics such as laptops can also be left in luggage, while clear plastic bags for liquids no longer have to be used. Other airports with the scanners include Gatwick, Bristol, Belfast Edinburgh and Birmingham which have increased to a two-litre