Nikki Haley, the US ambassador to the United Nations, has demanded the body’s security council hold Russia to account in the Trump administration’s strongest statement yet on the Salisbury attack.

She warned that a similar poisoning could be repeated in New York or other global cities in the future if the UN failed to take action.

Ms Haley said that Russia “is responsible” for the attack and warned of an "alarming" wider pattern of "dangerous and destabilising activity" from the country.

Ms Haley said: “If we don’t take immediate concrete measures to address this now, Salisbury will not be the last place we see chemical weapons used. They could be used here in New York or in cities of any country that sits on this council.

“This is a defining moment. Time and time again member states say they oppose the use of chemical weapons under any circumstances.