Theresa May has refused to criticise Donald Trump after he spurned her plea to challenge Vladimir Putin over the Salisbury nerve agent poisonings.

The prime minister was asked if she was “alarmed” by the failure to raise the attack - blamed on Russian military intelligence service – at the weekend talks between the two presidents.

Speaking in the Commons, Ms May confirmed she had asked Mr Trump to confront Mr Putin, when they spoke on his controversial trip to the UK just two days earlier.

But, instead, she pointed to his earlier response to the Salisbury attack, telling MPs: “The United States stood alongside us, as did many other nations across the world, and took action against Russia.”

Earlier, Ms May provoked howls of laughter when she argued she had been “agreeing the future of NATO with President Trump”, in their talks.

Mr Trump was briefed on the attempted assassination of Russian former double agent Sergei Skripal and his daughter Yulia in Salisbury in March.

The same batch of Novichok then killed Dawn Sturgess and left her partner Charlie Rowley critically ill last month.

Ahead of the Trump-Putin summit in Helsinki, Miss Sturgess's son Ewan said: “I would like him to raise mum's case with the Russian president. We need to get justice for my mum.”

Trump in Helsinki: Putin meeting and protests Show all 16 1 /16 Trump in Helsinki: Putin meeting and protests Trump in Helsinki: Putin meeting and protests President Trump meets with Russian President Vladimir Putin in Helsinki Reuters Trump in Helsinki: Putin meeting and protests An advert from Finnish newspaper Helsingin Sanomat is on display in Helsinki Reuters Trump in Helsinki: Putin meeting and protests President Trump in a meeting with Finnish President Sauli Niinisto AFP/Getty Trump in Helsinki: Putin meeting and protests President Trump meets with Finnish President Sauli Niinisto in Helsinki EPA Trump in Helsinki: Putin meeting and protests President Trump talks with Finnish President Sauli Niinisto in Mantyniemi, the official residence of the Finnish President EPA Trump in Helsinki: Putin meeting and protests US, Finnish and Russian flags fly in front of the Presidential Palace in Helsinki EPA Trump in Helsinki: Putin meeting and protests A protester wears a mask featuring a portrait of Russian President Vladimir Putin during the so-called "Helsinki against Trump and Putin" demonstration on July 16, 2018, in the Finnish capital Helsinki. The US and Russian leaders opened an historic summit in Helsinki on Monday, with Donald Trump promising an "extraordinary relationship" and Vladimir Putin saying it was high time to thrash out disputes around the world. / AFP PHOTO / Jonathan NACKSTRANDJONATHAN NACKSTRAND/AFP/Getty Images JONATHAN NACKSTRAND AFP/Getty Trump in Helsinki: Putin meeting and protests Vladimir Putin gifts a football to President Trump at the press conference that followed their meeting AP Trump in Helsinki: Putin meeting and protests Trump supporters hold banners during a demonstration in Helsinki AFP/Getty Trump in Helsinki: Putin meeting and protests People protest for women's reproductive rights in Helsinki's Senate Square Reuters Trump in Helsinki: Putin meeting and protests A crowd watches the motorcade transporting President Trump through Helsinki AFP/Getty Trump in Helsinki: Putin meeting and protests Russian President Putin drives through Helsinki on his way to meet with President Trump EPA Trump in Helsinki: Putin meeting and protests A man in the audience of the joint press conference holds up a sign sign that reads "NUCLEAR WEAPON BAN TREATY". REUTERS Trump in Helsinki: Putin meeting and protests A man is removed from the joint press conference in Helsinki. Security removed the man after he pulled out a sign that read "NUCLEAR WEAPON BAN TREATY". REUTERS Trump in Helsinki: Putin meeting and protests President Trump and Russia's President Putin sit for a working lunch in Finland's Presidential Palace AFP/Getty Trump in Helsinki: Putin meeting and protests President Trump meets with Russian President Vladimir Putin in Helsinki Reuters

At prime minister’s questions, Keith Simpson, a Tory backbencher, said Mr Trump had “acted in a very bizarre way over intelligence” in Helsinki.

“Is she not alarmed at the way he refused to challenge President Putin over the Russian activity which resulted, recently, in the death of a young women here in Salisbury?” he asked.

Ms May replied: “I did raise the incident in Salisbury, what happened in Salisbury and the fact that we have seen someone in the UK here die as result of contact with a nerve agent.

But, ducking what was said in Helsinki, she pointed to Mr Trump’s expulsion of 60 Russian diplomats in the immediate aftermath of the earlier poisoning.

“That gave the very clear message that we will not accept this behaviour. This is not behaviour that Russia can conduct with impunity and we will continue to act together,” the prime minister told MPs.