Countries across Europe must “step up” their defence capabilities and funding to protect Ukraine, UK Prime Minister Sir Keir Starmer has said.

The UK and Europe face a “generational challenge” and “need to do more” to defend Ukraine’s long-term security, he added.

His comments come ahead of an emergency meeting in Paris, where European leaders will discuss concerns the US is moving forward with Russia on peace talks that will lock out the continent.

US and Russian officials are to meet in Saudi Arabia on Tuesday, without representatives from Europe or Ukraine attending.

“We need to step up in terms of our collective response in Europe, and by that I mean capability,” Sir Keir said.

“By that, I mean playing our full part when it comes to the defence of the sovereignty of Ukraine if there’s a peace agreement.”

It comes after the prime minister said he was “ready and willing” to put UK troops on the ground in Ukraine to help guarantee its safety as part of a peace deal.

Sir Keir had previously only hinted that British troops could be involved in safeguarding Ukraine after a ceasefire.

“Securing a lasting peace in Ukraine that safeguards its sovereignty for the long term is essential” to deter Russian President Vladimir Putin from “further aggression in the future”, he wrote in the Daily Telegraph.

This means UK troops could be deployed alongside soldiers from other European nations along the border between Ukrainian-held and Russian-held territory.

But the former head of the British Army, Lord Dannatt, said this would come at a “considerable cost” and require an increase in military funding.

“Frankly, we haven’t got the numbers and we haven’t got the equipment to put a large force onto the ground for an extended period of time at the present moment,” he told BBC Breakfast.

The UK currently spends around 2.3% of GDP on defence. The government has committed to increasing defence spending to 2.5%, but has not said when this will be achieved.

Speaking in Bristol, Sir Keir told reporters that the government would set out a path to meeting the 2.5% commitment once it finishes its strategic defence review.

Lord Dannatt – who was head of the Army from 2006 to 2009 – told the BBC that 2.5% would be “nowhere near enough” and would only “fill the potholes” left by current underspending.

He has previously said the UK military was too “run down” to lead a peacekeeping mission in Ukraine.