Passengers were forced to sleep on the floor at London's Heathrow Airport overnight, media said on Saturday, after heavy snow grounded hundreds of flights and left thousands of people stranded. A spokesman for the airport, one of the busiest in the world, said a further 100 flights had been cancelled on Saturday morning, on top of about 400 that were grounded on Friday by the bad weather sweeping Britain. The Eurostar train service also reported further delays on Saturday, saying snow and ice in Britain and northern France had led to speed restrictions. It also cancelled two trains on Saturday. British media showed pictures of hundreds of people sleeping on the floor at Heathrow overnight on Friday. "There are lots of bodies lying around in the airport. If feels like there's been a natural disaster," Jerry Meng from Los Angeles, whose flight to New York was cancelled, told the BBC. Ian Aitchison, who was due to fly to the US for a conference, told the broadcaster he was feeling "mildly hysterical" after being stuck on a plane for more than six hours before the flight was cancelled. Runways, stands and taxiways remained open on Saturday but 67 outbound and 33 inbound flights were scrapped, largely because the bad weather meant aircraft or crew were not available, an airport spokesman said. "We do not expect significant snowfall today, but temperatures are forecast to remain around zero degrees or below. Passengers should check the status of their flight before travelling to the airport," he said. "There is a chance of further snow tomorrow." Heathrow invested 50 million pounds (60 million euros, $80 million) in improving its resilience to severe weather events after the chaos sparked by heavy snow in the run-up to Christmas to 2010, where passengers spent days stranded at the airport. London's other major airports at Gatwick and Stansted were expecting to operate normally on Saturday.