Russia’s intelligence agencies have long made it their business to gather political dirt from inside the Washington beltway, but allegations that the Kremlin is now using its capabilities to try to manipulate the US presidential election mark a new phase in the stand-off between Moscow and the west.

It has been over a month since US cyber security company CrowdStrike first alleged that Russian government-backed hacking groups were behind a breach of the Democratic National Committee’s computer network.

At first the attack was played down as an apparent exercise in political information gathering. But whoever leaked 20,000 sensitive emails on Friday, on the eve of the Democratic convention, to WikiLeaks clearly intended to shake up the convention.