This is reported by TASS with reference to the British authorities. 

“According to the British side, a window of opportunity has now opened in the conflict for greater effectiveness of the Armed Forces of Ukraine.

In this regard, London announced a "flurry of British diplomatic activity" in the coming week in order to attract allied military assistance to Kyiv.

Earlier it became known that Britain will transfer 14 Challenger 2 tanks to Ukraine in the coming weeks.