The 23 diplomats expelled by Britain left the Russian embassy in London

Britain is sharing intelligence on the 23 expelled Russian diplomats with other EU countries in a move that could trigger further expulsions across Europe.

Theresa May will set out the threat posed by “Russian networks” in other countries as Britain seeks a unanimous statement blaming the Kremlin for the attempted murder of Sergei and Yulia Skripal in Salisbury at the European Council summit today.

Sir Mark Sedwill, Britain’s national security adviser, was in Brussels yesterday to brief EU officials on London’s response, including what it claims to be the wholesale dismantling of Russia’s espionage network. As the names and ranks of the expelled “undeclared intelligence officers” circulate, other EU nations are understood to be considering similar expulsions.

The prime minister will seek to cast the