A Foreign & Commonwealth Office spokesperson said:
Our Ambassador in Moscow has just been informed by the Russian government that they will expel 23 diplomats, close the British Consulate-General in St Petersburg and close the British Council in Moscow.
This follows the action we have taken, alongside other measures, to dismantle the Russian espionage network operating in the UK as a consequence of the attempted assassination of 2 people here in Britain using a nerve agent.
In light of Russia’s previous behaviour, we anticipated a response of this kind and the National Security Council will meet early next week to consider next steps. Our priority today is looking after our staff in Russia and assisting those that will return to the UK.
Russia’s response doesn’t change the facts of the matter – the attempted assassination of 2 people on British soil, for which there is no alternative conclusion other than that the Russian State was culpable. It is Russia that is in flagrant breach of international law and the Chemical Weapons Convention.
We have no disagreement with the people of Russia and we continue to believe it is not in our national interest to break off all dialogue between our countries but the onus remains on the Russian state to account for their actions and to comply with their international obligations.