Ministers are being accused of dragging their feet over a promised crackdown on corrupt Russian officials using London as a “playground”.

Four months on from the introduction of a new law targeting human rights abusers with visa bans and asset freezes, the government has failed to publish a list of those facing the sanctions, despite assuring MPs that it would do so.

Campaigners said there was “no excuse” for the delay, pointing out that Canada had issued a similar list one week after publishing equivalent legislation last year.

The so-called Magnitsky law, which forms part of the Sanctions Act, was passed in May in the wake of the chemical weapons attack in Salisbury, which the government said was a Kremlin-ordered assassination.

Last week Theresa May cited the "Magnitsky amendment" as a key part of the Government's response to the Salisbury attack.