Swathes of Eastern Scotland, Wales, East Midlands, Yorkshire, Lancashire and North East England were smothered in a thick blanket of snow, with gale force winds creating drifts of up to six metres (20ft).
Farmers made desperate attempts to rescue missing sheep – many of which were in lamb – but were overcome by arctic-like blizzards.
But there was hope amid the spring gloom as rural bodies stepped up to offer help, with the Prince’s Countryside Fund setting aside more cash for struggling farmers.
Cumbria beef and sheep farmer and former NFU livestock board chairman Alistair Mackintosh said thousands of sheep had ‘vanished’.
He said: “The conditions are absolutely hellish out there. It took us three days to get our sheep dug out and we lost about 100 lambs in all.”
But Mr Mackintosh feared the true extent of the catastrophe would not be known until the thaw had set in.
“This is a national disaster as it is but we will see just how bad things are when the snow melts,” he added. “Now we need the public to support us and buy British lamb and make all this hard work worthwhile.”
Gareth Wyn Jones, who was working to rescue 3,500 sheep at his farm in Conwy, Wales, said some lambs had been born frozen to the ground.
NFU vice-president Adam Quinney said farmers were working around the clock to clear roads in order for lorries to deliver feed.
He added: “It has put an extraordinary strain on the industry after what has been a torrid 12 months of extreme weather.”
Farmers on the Isle of Man were battered with the island’s heaviest snowfall since 1963, prompting young farmers to join the relief effort and help dig out trapped sheep.
In Northern Ireland, helicopters were scrambled to drop animal feed into some of the worst-hit areas in the Glens of Antrim.
The Scottish Government also sprang into action to help farmers in Arran and Kintyre, where thousands of properties have been without power for days.
It comes as the National Fallen Stock Company urged livestock disposal firms to consider discounts for more than 10 animals, with the death toll expected to rise further.
Supermarket giant Waitrose said it would send 25,000 plastic lamb macs to its suppliers still struggling to provide accommodation for lambing sheep.
Concerns are also running high on arable farms, with growers reporting they were ‘way behind’ with sugar beet planting, but British Sugar said there was still time in the planting window.
Seed manager at Hutchinsons, Colin Button, added if the grim situation continued, growers would ‘have to make some decisions about returning seeds’.