It has been predicted for more than a week but large parts of London and south-east England have been halted by an unusually heavy snowstorm.The capital has been covered by a thick blanket of snow following one of the largest flurries in almost two decades. It has caused travel chaos with several London Underground lines shut along with bus and train services. Flights to and from all airports are subject to delays or cancellations. Many schools and offices have also been forced to close for the day. The scene was the same in Paris this morning where transport teams were out early to clear and grit frozen roads before rush hour. But that did little to prevent dozens of accidents. Large parts of Belgium, Spain and Italy have also been hit and some forecasters say it may get worse with up to 20 centrimetres expected to fall in some areas of Europe later this week.