On 5th September 2018, the former Prime Minister updated the House of Commons on the investigation into the two suspects involved in the Salisbury attack. The Prime Minister confirmed that traces of Novichok were found at the City Stay Hotel in Bow Road, east London, where the suspects stayed. This statement was repeated in the House of Lords on the same day by the Leader of the House of Lords. This can be found in Hansard Vol 792, col.1799 http://bit.ly/2ycrsCk.
The Chief Medical Officer made it clear in her statement on the 5th September 2018 that the room was only allowed back into use after experts deemed it to be safe.