Russia's foreign and defence ministers visited Britain for high-level talks on Wednesday in a further thawing of ties once frozen by the murder of dissident Alexander Litvinenko in London.

Foreign Minister Sergei Lavrov and Defence Minister Sergei Shoigu met with their British counterparts William Hague and Philip Hammond for the first of what are hoped to be annual talks on security, defence and foreign policy.

Britain's Foreign Office said the new dialogue was "an important milestone" in British-Russian relations, showing the "extent of progress in developing a mature relationship at a senior level".

The Russian ambassador to London, Alexander Yakovenko, said it was "another step in the right direction for the relationship between our two nations".

Ties between Britain and Russia were severely strained by the 2006 death by radioactive poisoning of former Russian spy turned dissident Litvinenko in London.

British police have said their chief suspect is Andrei Lugovoi, a former Russian agent who is now a lawmaker, but Moscow has refused to extradite him.

Relations have warmed in recent years, however, with Prime Minister David Cameron visiting Moscow in 2011 and President Vladimir Putin making his first trip to London for seven years last August for the Olympics.

The two leaders disagree on their approach to the Syrian crisis, with Britain frustrated at Russia's refusal to back calls for President Bashar al-Assad to step down.

But both sides appear keen to build bridges.

"Russia is open for cooperation with all those who wish it. This undoubtedly applies to the United Kingdom," ambassador Yakovenko wrote in an article for British website Politics Home on Wednesday.

"In the past our bilateral relations have become hostage to ill-conceived suspicions and prejudices. Fortunately, the last two years have seen ice melting, slowly but gradually."

The British and Russian ministers were due to give a joint press conference on Wednesday afternoon.