The Ministry of Defence is considering the possibility of sending British troops to Ukraine to help train its armed forces.
Defence Secretary John Healey has been in the capital Kyiv to discuss plans to provide more support to Ukraine in the coming year.
He declined to give details of those plans, but defence sources say he has not ruled out the move.
Britain has been training Ukrainian troops in the UK since 2022. There is also a small team of British Army medics providing training inside Ukraine.
Healey declined to give specifics on what the additional support could be, saying the plans would "have to remain, let's say, unavailable to [Russian] President [Vladimir] Putin".
The UK and other Nato members have not sent troops to Ukraine or enforced a no-fly zone over the country, for fear of being pulled into a direct conflict with Russia. However, individual members have supplied arms and equipment.
Healey came to Kyiv with the promise of an additional £225m of military support – for more drones, artillery shells and air defences.
But he said he had also been discussing how to put Ukraine in the strongest possible position for the coming year. That, he said, involved more weapons, more training and more sanctions on Russia.
US President-elect Donald Trump has promised to try to bring an end to the war. Some Western nations have been discussing how they might provide security guarantees for Ukraine should that happen.
Healey said he would wait to see Trump's plans but the defence secretary said his primary duty was to do everything possible for Ukraine while it continued its fight.
His comments come ahead of a meeting in Brussels on Thursday, which will be attended by Foreign Secretary David Lammy and Ukrainian President Volodymyr Zelensky, as well representatives of EU countries and Nato.
Lammy, echoing the defence secretary, said the discussion would focus on what further support was needed to "put Ukraine in the strongest possible position as we head into and through 2025".
"It is hugely important that allies right across Europe step up in that support they are giving Ukraine, the training that is still necessary for their armed forces, the finances that we still need over the longer term, and we have to find innovative ways to find that finance," he added.
The situation in Ukraine was also discussed when Prime Minister Sir Keir Starmer spoke to Trump during a phone call on Wednesday.
"The Prime Minister reiterated the need for allies to stand together with Ukraine in the face of Russian aggression and to ensure Ukraine is in the strongest possible position," said a Downing Street spokesperson.
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