The Kremlin on Friday said it was "not optimistic at all" about any change in difficult relations between Britain and Russia following Labour's victory in the UK general election.

"As far as we can see from their previous statements, they are not inclined to any flexibility or creativity in normalising bilateral Russian-British relations," Kremlin spokesman Dmitry Peskov said.

"They are instead aiming to continue the line of denying the future of our bilateral relations," Peskov said.

Britain has taken a lead in rallying Western support for Ukraine and has slapped sanctions on Russia following the launch of Moscow's offensive against Ukraine in February 2022.

Relations were at a low even before the conflict began, particularly after London blamed the 2018 poisoning of former Russian spy Sergei Skripal and his daughter Yulia on Russian agents.

Ukrainian President Volodymyr Zelensky on Friday congratulated Labour leader Keir Starmer on his landslide victory.

"Ukraine and the United Kingdom have been and will continue to be reliable allies through thick and thin. We will continue to defend and advance our common values of life, freedom, and a rules-based international order," Zelensky said.