The UK should supply Ukraine with long-range missiles to “bring the war to an end,” former British prime minister Boris Johnson has said.

The conservative politician has called for greater Western assistance for Ukraine, including supplying the war-torn country with longer-range missile systems.

Defence Secretary Ben Wallace said he constantly reviews the “weapon systems we could provide” and is “open-minded to seeing what we do next” should Russia continue to target civilian areas and break the Geneva Conventions.

However, Downing Street indicated the UK is not planning to provide long-range missiles to Ukraine.

Prime Minister Rishi Sunak’s official spokesman said: “You will know that the military equipment that we provide to Ukraine is for use in Ukraine to enable it to defend itself against the illegal invasion.”

“I’m not aware of any plans to alter that approach but obviously we keep these things under review.”

Speaking in the Commons during defence questions, Johnson said: “The House will know that supplies of British, American and other Western equipment have been absolutely vital in helping our Ukrainian friends to protect themselves against continuing and merciless Russian attacks, and I thank him and the Government for all that they have done and continue to do.”

“Does he agree with me that we and our allies must help our Ukrainian friends not just to take out the drones and missiles, and that means supplying them with anti-aircraft systems and fixed-wing aircraft to help shoot them down, but also to take out the launch sites of those missiles and drones by supplying the Ukrainians with the use of longer-range missile systems such as ATACMS (Army Tactical Missile System) because that is the way truly to protect our Ukrainian friends and to bring the war to an end as soon as possible?”

Wallace paid tribute to Johnson, saying: “Without my right honourable friend’s support to me and Ukraine, none of this would have been possible and I want to place on record my great appreciation for his support through that process.”

He added: “He’s absolutely right that the Russians are taking advantage of the short-range capability of the Ukrainian armed forces by using these Iranian kamikaze drones.”

“As we see against all the rules of law, including the Geneva Conventions, the mass targeting of civilian critical infrastructure is not only a war crime, but is a war crime that we must see does not go unpunished.”

“I constantly review the weapon systems we could provide. I hear his call on ATACMS from the United States.

“We, too, have in our armoury potential weapon systems that are longer and, should the Russians continue to target civilian areas and try and break those Geneva Conventions, then I will be open-minded to seeing what we do next,” Wallace asserted.