To Russia, the Yantar is a oceanic research vessel - to others, including the UK, it's a spy ship, and a worry for Britain's defence chiefs.

The vessel has long been suspected of secretly mapping out Britain's undersea cables, where more than 90% of our data, including billions of dollars of financial transactions, are transferred.

But now, a new escalation, with revelations the Yantar's sailors targeted Royal Air Force pilots in patrol planes with lasers.

Shining lasers into a pilot's eyes is provocative, and to use the Defence Secretary John Healey's words, "deeply dangerous". It's illegal in the UK and can lead to a prison sentence.

Healey's direct message to Russia and its leader Vladimir Putin was stark: "We see you. We know what you're doing. And if the Yantar travels south this week, we are ready."

By that, he is implying should the Yantar cross inside Britain's 12-mile maritime boundary there would be a military response.

This isn't the first time the Yantar has popped up near Britain's shores - at the start of the year a Royal Navy submarine made the highly unusual move to surface right in front of the ship as a sort of deterrent measure.

The concern is that this is part of an ongoing operation by the Kremlin to locate and map all the vital undersea cables and pipelines that connect the UK to the rest of the world.

It is also part of a wider pattern of Russian activity, as it tests Nato's reactions, resolve and defences. We've seen similar moves with the recent drone incursions across Europe, and Russian warplanes flying into Nato airspace.

When three Russian fighter jets entered Estonian skies without permission in September, Italy, Finland and Sweden scrambled jets under Nato's mission to bolster its eastern flank.

This is all interesting intel for Russia.

As an island nation, Britain is heavily reliant on its network of undersea cables that carry data. There are also vital oil and gas pipelines connecting Britain to North Sea neighbours such as Norway.

These cables and pipes are largely undefended and apparently of great interest to Russia's research vessels.

Nato has identified deep-sea cables as part of the world's critical infrastructure. But they are also strategic pressure points, it says, warning that adversaries could exploit them through sabotage or hybrid warfare, threatening both civilian and military communications.

Retired Royal Navy Commander Tom Sharpe made clear what the spy ship could be doing: "The most obvious one is they sit above our cables and our critical undersea infrastructure and they nose around in the cables that transfer up to $7tn worth of financial transactions every day between us and America alone".

The Yantar may be described by Moscow as a research vessel, but it is part of Russia's secretive Main Directorate for Deep Sea Research, or GUGI, which reports directly to the defence ministry.

And while the ship bristles with hi-tech communications equipment, it's what we can't see that is of most concern.

It can operate remotely-piloted miniature submarines that can dive down to sea beds many thousands of metres below the surface. These are capable of mapping the locations of cables, cutting them or planting sabotage devices that could, potentially, be activated in a time of war.

The Royal Navy is experimenting with various means of combating the threat, such as a new vessel called Proteus, but critics fear much of the damage to Britain's coastal security may already have been done.

Any foreign vessel operating in British waters must comply with UK national laws and international maritime conventions.

The cornerstone of these complex rules is the UN Convention on the Law of The Sea (UNCLOS). This allows foreign ships to navigate through coastal waters provided that their passage is "innocent" - meaning it doesn't threaten the peace or security of a coastal nation like Britain.

President Putin was at an AI conference in Moscow on Wednesday, and gave no immediate reaction on the situation unfolding north of Scotland.

Russia's Embassy in London says it's not undermining UK security and it has condemned UK Defence Secretary Healey's statement as provocative.

But all this is happening while war rages in Ukraine, a conflict Putin blames on the West and which seemingly he has no intention of stopping soon.

Additional reporting by Tiffany Wertheimer and Stuart Hughes

Wintry weather is set to continue across the UK on Thursday - with temperatures forecast to fall below zero overnight, and snow and ice affecting some areas.

Met Office yellow warnings are in place for Northern Ireland, northern and central Scotland, and coastal areas in south-west Wales, and south-west, east and north-east England.

A more severe amber warning is due to come into force later in the North York Moors, where as much as 15-25cm (6-10ins) of snow could fall on higher ground.

The UK Health Security Agency (UKHSA) has also issued cold-health alerts for England until Saturday, saying there could be "significant" impacts to the elderly and people with health conditions.

Areas from London to Shetland saw snow on Wednesday.

There were dozens of school closures in north-east Scotland and the Highlands and road closures on the Woodhead Pass between Hollingworth and Flouch in Derbyshire and the B4391 between Rhyd y Sarn and Pen y Bryn in north-west Wales.

Temperatures on Wednesday night could fall to as low as -5C (23F) in Scotland and northern England, and -3C (26.6F) in other parts of England and east Wales.

With a frost expected, areas where showers or rain and sleet have left the ground damp are at risk of ice becoming a hazard on roads and pavements. Forecasters warn that buses and trains may be cancelled or delayed.

But the conditions are unlikely to resemble the snowy and icy spell this time last year which closed hundreds of schools and saw 12cm of snow in Nottingham.

Over recent decades the Met Office have observed a decrease in the frequency, duration, and intensity of cold spells, clearly linked to climate change. According to the latest State of the Climate Report, external, air and ground frosts have reduced by around a quarter since the 1980s.

Yellow warnings

• There are yellow warnings for snow and ice on Thursday in:

• Cornwall and parts of Devon, and Carmarthenshire, Ceredigion, Pembrokeshire and Swansea until 23:59 GMT

• North East England, SW Scotland and Lothian Borders, Yorks & Humber until 23:59 GMT

• Central and northern Scotland until 21:00 GMT

• Norfolk, Suffolk, Cambridgeshire and Lincolnshire until 11:00 GMT

• Northern Ireland until 12:00 GMT

'Thundersnow' forecast

Thursday's amber warning for North Yorkshire is in place from 03:00 to 2100 GMT. Forecasters say snow is expected throughout the day, mostly on hills above 100m elevation and could lead to "substantial disruption".

They say it is possible some areas, including the North York Moors and the Highlands of Scotland, could see what is known as thundersnow.

It is is a phenomenon which happens when thunderstorms form in wintry weather and give rise to heavy falls of snow rather than rain.

Meanwhile, in Wales, the snow warning is linked to what forecasters dub the "Pembrokeshire Dangler". This is a line of showers that develop over the warmer waters of the Irish Sea and are pushed southwards over the county of Pembrokeshire in south-west Wales.

Daytime temperatures in most areas of the UK on Thursday will reach between 4C and 6C.

Temperatures are expected to become milder by the weekend, rising to average levels by Saturday.

Amber cold-health alerts have been issued in England by the UKHSA until 08:00 GMT on Saturday for the North West, North East, and Yorkshire and Humber, with all other areas under less-severe yellow alerts.

The alerts are mainly for health and social care services, warning of "significant" impacts to more vulnerable members of the community.

Extra demands may be put on services to deal with colder weather.

Albania's prime minister accused Home Secretary Shabana Mahmood of "ethnic stereotyping" after she singled out Albanian families in a speech about abuses of the asylum system.

Edi Rama criticised Mahmood for telling MPs around 700 Albanian families were "living in taxpayer-funded accommodation having failed their asylum claims" as she announced major reforms on Monday.

Rama called the number a "statistical drop in the ocean of post-Brexit Britain's challenges".

Official data show the UK has deported more than 13,000 people to Albania since a returns deal was signed in 2022. Rama called the deal one of "Europe's most successful partnerships on illegal migration."

Mahmood's comments came as she announced major changes to the UK's "out of control and unfair" asylum system.

Speaking in the House of Commons, Mahmood said: "If we fail to deal with this crisis, we will draw more people down a path that starts with anger and ends in hatred."

The reforms will make refugee status temporary, extend the wait for permanent settlement from five years to 20, and allow the removal of families with children who have no right to remain.

Alongside tightening access to refugee status, the UK would create new legal routes to the UK, with an annual cap on numbers.

As part of her speech, Mahmood told MPs "we must remove those who have failed asylum claims, regardless of who they are".

"There are, for instance, around 700 Albanian families living in taxpayer-funded accommodation having failed their asylum claims - despite an existing returns agreement, and Albania being a signatory to the European convention on human rights," she added.

Posting on social media, Rama said: "How can a Labour Home Secretary so poorly echo the rhetoric of the populist far-right – and single out 700 Albanian families, a statistical drop in the ocean of post-Brexit Britain's challenges – precisely at a moment when the UK and Albania have built one of Europe's most successful partnerships on illegal migration?"

"Let us also be clear: Albanians are net contributors to the British economy, and the number of Albanians receiving UK benefits is very low relative to other communities.

"To single them out again and again is not policy - it is a troubling and indecent exercise in demagoguery.

"Official policy should never be driven by ethnic stereotyping. That is the very least humanity expects from the great Great Britain."

Rama has repeatedly clashed with British politicians over their descriptions of Albanian nationals.

In May, Sir Keir Starmer travelled to the Albanian capital Tirana only to be told by Rama he would not host UK "return hubs" for failed asylum seekers from other countries.

During the same press conference, Rama accused the previous Conservative government of "stigmatising" Albanians and warning that "cursing the Albanians was not a good idea, because the curse went back and they are now out of the parliament".

A combative figure on social media, Rama has also previously invited Reform UK leader Nigel Farage to come to Albania to debate his claim one in 50 Albanians in Britain were in prison.

Rama dismissed the figure as "bonkers" and accused Farage of peddling "post-truth Brexit playbook" politics.

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Chip giant Nvidia beat Wall Street's expectations for revenue and upcoming sales, easing investor concerns about heavy artificial intelligence (AI) spending that have unsettled markets.

In its quarterly earnings report on Wednesday, the firm said revenue for the three months to October jumped 62% to $57bn, driven by demand for its chips used in AI data centres. Sales from that division rose 66% to more than $51bn.

Fourth-quarter sales forecasts in the range of $65bn also topped estimates, sending shares in Nvidia more than 3% higher in after-hours trading.

Nvidia, the world's most valuable company, is seen as a bellwether for the AI boom. The chip-maker's results could inform market sentiment.

Chief executive Jensen Huang said in a statement that sales of its AI Blackwell systems were "off the charts" and that "cloud GPUs [graphics processing units] are sold out".

The chip-maker's quarterly report garnered even more attention than usual on Wall Street amid mounting concern that AI stocks are overvalued.

Those fears had fueled four consecutive daily drops in the S&P 500 index leading up to Wednesday, as questions swirl about returns on AI investments.

Italy's top appeals court has ruled that a Ukrainian man suspected of involvement in blowing up the Nord Stream gas pipelines between Russia and Germany should be extradited to Berlin.

There, former Ukrainian military officer Serhiy Kuznetsov will face a charge of anti-constitutional sabotage. He is due to be removed from Italy under German police escort in the next few days.

Prosecutors believe Mr Kuznetsov coordinated and led a group that planted explosives on the pipes deep beneath the Baltic Sea in 2022, though they have not disclosed any evidence.

The case has serious implications for relations between Ukraine and Germany, which is the biggest source of military aid for Kyiv in Europe.

Mr Kuznetsov's lawyer said his client "feels like a scapegoat" and is "very sad" that his government has not spoken out in his defence, or even confirmed that he was a serving soldier at the time of the blasts.

"If he carried out the attack, then he did so because he was ordered to do so because he was for sure a captain of the Ukrainian army," Nicola Canestrini said after Wednesday's hearing.

The BBC has seen a copy of Mr Kuznetsov's military ID among the court papers. He has not commented publicly on whether he was involved in the explosions.

"The Ukrainian government knows exactly where he was every day of September 2022," his lawyer said. "So, if he's innocent, why don't they say it? If he did it, why don't they say it? That's his question."

The BBC has approached government and security sources in Kyiv, but they have not commented.

Mr Kuznetsov was arrested in northern Italy in late August, at a glamping site near the city of Rimini where he had booked in for a few nights with his wife and two of their children.

His passport details were entered online at check-in, and in Italy that information is automatically transferred to the carabinieri, the local police.

Later that night, officers came knocking at the family's door.

A month later, a second Ukrainian suspect was detained at his home close to Poland's capital Warsaw on another arrest warrant issued by Germany.

Volodymyr Zhuravlyov, an amateur deep-sea diver, has lived in Poland with his family since just before Russia's full-scale invasion of Ukraine in 2022.

He was held in custody for 17 days, but a court then refused to extradite him.

The judge delivered a passionate speech, arguing that no Ukrainian could be prosecuted for what he characterised as a legitimate act of self-defence against Russia's "bloody and genocidal" invasion of Ukraine.

In Italy, further from Ukraine, the mood and the politics are very different.

Mr Canestrini described the Italian appeal court's ruling as a "great disappointment", but said the fight for his client would now move to Germany - with the aim of having Mr Kuznetsov acquitted on the same grounds.

Many Ukrainians consider whoever did destroy Nord Stream to be heroes for taking out an important revenue source for Russia, and struggle to understand why Germany - a key ally of Ukraine - is pursuing this prosecution.

On Wednesday, one man stood outside the palatial courthouse in Rome wrapped in a Ukrainian flag and holding a poster that read: "Serhiy Kuznetsov is a defender, not a criminal."