Theresa May urges Trump to raise novichok poisonings with Putin during Helsinki meeting

'As long as Russia persists in its efforts to undermine our interests and values, we must continue to deter and counter,' prime minister says

The prime minister will focus on the Salisbury attacks when she meets the president at Chequers during his visit to the UK (Reuters)

Theresa May will ask Donald Trump to raise the novichok attacks in Wiltshire when he meets Vladimir Putin in Helsinki – and press the Russian president to provide any relevant information which may prevent further victims from the nerve agent used in Salisbury.

The British prime minister will focus on the attacks when she meets the US president at Chequers during his visit to the UK, starting on Thursday, following the Nato summit in Brussels.

She also warned fellow Nato leaders at a working dinner that the Kremlin is engaged in a pattern of behaviour, such as the nerve agent attack in Salisbury, which is intended to “undermine our democracies and damage our interests around the world”.

Ms May said the alliance must work together “to raise the cost of malign behaviour whenever it occurs”, including working together on cyberattacks and taking action against intelligence networks of hostile states in their own countries where they act against Western interests. She also said Nato members must agree on implementing and maintaining robust sanctions when countries violate international norms.

“As we engage Russia, we must do so from a position of unity and strength – holding out hope for a better future, but also be clear and unwavering on where Russia needs to change its behaviour for this to become a reality,” she said.

“And, as long as Russia persists in its efforts to undermine our interests and values, we must continue to deter and counter them.”

However, Ms May also said she welcomed Mr Trump’s meeting with Mr Putin. She said: “Our long-term objective remains a constructive relationship with Moscow. If we are to be successful in this we must keep engaging individually and as an alliance.”