Britain's intelligence chief optimistic Ukraine will prevail against Russia

Britain's intelligence chief has said he is "optimistic" Ukraine will prevail in its war against Russia, whose forces have lost momentum on the battlefield.

Richard Moore said Ukraine has "recovered more territory in a month than the Russians managed to achieve in a year" and that "there appears to be little prospect of the Russian forces regaining momentum," CNN reports.

It will be up to Kyiv to "define" the end of the war, as "most conflicts end in some kind of negotiation," he added during a speech in Prague on July 19. 

Moore's words come as Ukraine continues its spring counteroffensive against Russian troops. Since the counteroffensive began in June, the fighting has proved tougher than some anticipated, with progress being measured in hundreds of meters as opposed to tens of kilometres.

Ukraine had hoped to use the push to expel a significant amount of Russian forces from Ukrainian soil and turn the tide of the war.