RUSSIA'S intelligence capability has been fundamentally degraded for years to come by the Western response to the nerve agent attack in Salisbury, Theresa May will say.

The Prime Minister will use a speech at the Lord Mayor's Banquet in London today to praise international support after the UK blamed Moscow for the incident.

Mrs May will condemn what she brands "the reckless use of a chemical weapon on our own streets" by Russia's GRU intelligence service as she calls on Western powers to continue to stand together.

The PM will say: "Together with our allies, in response to the attack in Salisbury, we coordinated the largest ever collective expulsion of Russian intelligence officers, fundamentally degrading Russian intelligence capability for years to come.

"And our law enforcement agencies, through painstaking investigations and cooperation with our allies, produced the irrefutable evidence that enabled our Crown Prosecution Service to bring charges against those responsible.

"In response to the activities of the GRU in Europe, through the cooperation of Western security agencies, the Dutch government were able to prevent and expose Russian attempts to penetrate and undermine the Organisation for the Prohibition of Chemical Weapons.

"In these actions, we have seen the impact of international unity and a collective response to these threats.

"We have shown that while the challenge is real, so is the collective resolve of like minded partners to defend our values, our democracies, and our people."

But the Prime Minister will say the UK is ready for better relations with Moscow.

"We remain open to a different relationship - one where Russia desists from these attacks that undermine international treaties and international security - and instead acts together with us to fulfil the common responsibilities we share as permanent members of the UN Security Council," she will say.

"And we hope that the Russian state chooses to take this path. If it does, we will respond in kind."

The UK accused the GRU of carrying out the poisoning of ex-spy Sergei Skripal and his daughter Yulia with Novichok in Salisbury in March.

Russia has also been blamed for the death of 44-year-old Dawn Sturgess and the poisoning of her partner Charlie Rowley, who are believed to have come into contact with Novichok discarded by the Skripals' attackers.

Meanwhile, the Prime Minister will also use the speech to name one of the eight planned Royal Navy Type 26 frigates as HMS London.