Newspaper headlines: 'Blackout threat' as UK 'stands up' to Putin
As relations between the UK and Moscow deteriorate after the Salisbury attack on a former Russian spy, the Sunday Times says Britain's intelligence agencies have issued a warning to the heads of key power companies.
The paper says they have been told to improve their security because of fears of a Russian cyber attack aimed at putting the lights out.
Whitehall departments and NHS hospitals, adds the paper, have also been told to prepare for attacks which could steal data or close down websites.
The Mail on Sunday says Theresa May is to launch a crackdown on what it calls the "dirty money" that allies of Vladimir Putin have sheltered in London.
The paper calls them his "McMafia cronies" - a reference to the recent BBC crime drama - and says there could be emergency legislation to seize Russian assets.
'Help of friends'
According to the Sunday Express, a thousand Russian oligarchs could face travel bans.
An editorial in the Observer argues that Britain cannot manage this crisis alone - it needs the help of friends and allies to force Putin to back off.
The Independent has spoken to a former UK ambassador to Russia, Sir Rodric Braithwaite, who has criticised ministers for "shooting their mouths off" over the crisis.
He says some comments have been much too wild - although he praises Theresa May's handling of the situation.
The Sunday Telegraph's Brexit correspondent has been to look at the border between Norway and Sweden, to see whether it could be a blueprint for a frictionless UK border after leaving the EU.
The president of the Swedish customs service tells the paper that the border is 85% per cent smart - and that a British border would need even better technology.
The Mail on Sunday reports on research which modelled what would happen if lorry checks at the Channel Tunnel took four minutes rather than the current two. The result, apparently, would be a 29.3 mile tailback in Kent.
The paper has also been to the Norway-Sweden border, and found that checks there could take nine minutes.
'Too much trouble'
The Observer leads with its claims about the data company, Cambridge Analytica, allegedly using the details of millions of Facebook users.
Its front page has a picture of the whistleblower, Christopher Wylie, whose allegations are now being looked into by officials in the US and Britain.
The Observer has studied documents jointly with the New York Times, with both papers publishing allegations that the profiles of up to 50 million people may have been affected. Both the company and Facebook have denied any wrongdoing.
The Sunday Mirror leads with claims that police who investigated sex abuse suspects in Telford decided it was "too much trouble" to take out court orders against them.
The paper says the information has come from an officer who says he was horrified by the decision. Assistant Chief Constable of West Mercia Police, Martin Evans, has denied the claim, telling the Mirror that other measures were put in place instead.
Second cold snap
There are plenty of pictures of snow.
The Independent shows cars stuck on the A66 trans-Pennine road, while the Sunday Telegraph has a more tranquil scene, with ponies sheltering from the snow in Cumbria.
The Sunday Times also chooses Cumbria, with a picture of a decidedly wintry model village.
The Observer pictures the snowy Pennines near Saddleworth - but warns that the second cold snap could have serious consequences for wildlife.
It reports that experts fear the insect population will be reduced, causing food shortages for birds and other creatures.
The paper says it is a far cry from the days when every child was mother's little helper.
It adds that the Good Housekeeping Institute has come up with a list of chores every child should learn how to do, including washing up, emptying the dishwasher, making beds, watering plants, and basic baking.