Thousands of flights and train services have been cancelled across Europe because of snow and ice, leaving many travellers stranded. Few flights were leaving London Heathrow airport while one third flights were cancelled in major hubs like Paris and Frankfurt. Departures from Brussels airport were to be cancelled until Wednesday due to a lack of de-icing liquid. Roads in a number of countries have been described as treacherous. The UK, France and Germany were among the worst-hit countries, with forecasters warning of freezing weather all week. There were also severe delays on the Eurostar rail service between the UK and France. Thalys trains between France and Belgium were also affected.Lines of delayed passengers formed outside London's St Pancras station as speed restrictions hit rail travel in England and northern France. Eurostar urged travelers to cancel or postpone their trips if possible. In Germany, rail services were also affected. Heavy snow in Berlin caused problems for commuter trains and on the roads.