The head of the UK's Intelligence Agency is due to give a security speech in London in which he's expected to say Ukraine is " turning the tide" against exhausted Russian forces.

英国情报局局长将在伦敦发表安全讲话，预计他将在讲话中表示，乌克兰正在“扭转局势”，抵抗疲惫的俄罗斯军队。