Britain has accused the Kremlin of being behind cyber attacks on UK soil and summoned the Russian ambassador to the Foreign Office. It came as Joe Biden imposed tough new economic sanctions on Moscow, and expelled 10 Russian diplomats, over the same SolarWinds hack that caused chaos to US government computer systems last year. For the first time, the UK's National Cyber Security Centre, the defensive branch of GCHQ, confirmed that a "low single-digit number" of public sector organisations had been hit, although it said the impact had been "low". It refused to confirm reports that NHS trusts were among the infiltrated targets, but a Government source said the "objective was espionage, aiming to obtain information". At the Foreign Office, Sir Philip Barton, the Permanent Under Secretary, expressed Britain's "deep concern" to Andrei Kelin, the Russian ambassador, over a "pattern of malign activity" including cyber attacks, interference in democratic processes, and the build-up of military forces near Ukraine. The ambassador was told the Kremlin "needs to cease its provocations".