Forecasters warned there was no end in sight for icy conditions as the death toll rose and transport networks struggled to cope with the freezing weather.

Two pensioners died after falling in their gardens in sub-zero temperatures, while a motorist who stopped to help a stranded driver died after he was struck by another vehicle.

As a working week beset by major disruption comes to an end, commuters face continuing chaos on the trains and drivers were warned of the danger of black ice on roads.

Transport Secretary Philip Hammond summoned Government chiefs for an hour-long emergency weather meeting on Friday to "stocktake" and discuss preparations for the weekend, a Downing Street spokeswoman said.

Though the worst of the snow has fallen, temperatures remain low and rain is set to make Britain's frozen roads and pavements even more dangerous.

"The problem is the ground temperature is lower than the air temperature so makes thawing difficult," said Aisling Creevey, a forecaster with Meteogroup."It's going to be really cold into the next 10 days."

There might be a slight reprieve on Saturday for the south of England with a rise in temperatures to about 5C expected. But that will not be enough to melt the ice which is expected to be worsened by rain freezing on top. Any thaw will "be a very slow process", said Miss Creevey. "It's a big, icy mess - I would be really advising caution, it is going to take time to thaw out."

The warning came as details emerged of the first casualties.

Police said they feared 80-year-old Lillian Jenkinson had frozen to death after collapsing in her back garden in Workington, Cumbria. Her body was found at 10.40am on Thursday, the day after an elderly man was found dead in his garden in Kirby Stephen, also in Cumbria.The deaths prompted charities to urge residents to check on elderly neighbours.

Meanwhile, North Yorkshire Police said a 57-year-old man, who has not been named, was standing behind his Land Rover Defender when he was struck by a Land Rover Freelander. He had stopped to help recover a Vauxhall Corsa from a ditch at Bellerby Bank, between Richmond and Leyburn, on the edge of the Yorkshire Dales, when the accident happened at 7pm on Thursday.