It was unclear if Williamson was referring to the attack on the Skripals or a new attack. "Charlie is still very unwell and will continue to require specialist, round-the-clock care here at Salisbury District Hospital", the statement said.
Metropolitan Police Assistant Commissioner Neil Basu said it was implausible that the attack on the Skripals in Salisbury in March, and the poisonings nearby of Ms Sturgess and Mr Rowley were not linked.
Sturgess and Rowley fell ill on June 30.
A Bristol distillery has apologised for launching a vodka named Novichok a day before the substance killed victim Dawn Sturgess in Amesbury.
Yulia Skripal was discharged from hospital in April and her father was discharged in May.
The backdrop to this meeting was British but the issue was global as police issued a Novichok warning to the residents of Salisbury.
Watchdog urges record £500000 fine for Facebook over Cambridge Analytica data scandal
However, Sky News notes that the £500,000 fine will be "pocket change" for a company valued a year ago at around $590bn (£445bn). It also found that the company failed to be transparent about how people's data was harvested by others".
Britain has blamed Russian Federation for the attack on the Skripals - a charge strongly denied by Moscow which has challenged British authorities to publish the evidence.
Police officers guard a cordon in Salisbury, one of five locations in the city and Amesbury under investigation.
He said 100 detectives were working on the investigation, which was now focused on on Ms Sturgess's address within John Baker House in Salisbury, Mr Rowley's address in Muggleton Road, Amesbury. and an area in the Queen Elizabeth Gardens in Salisbury.
Ms Sturgess, who had a daughter aged 11 and two sons aged 19 and 23, had...
Police seized a vehicle in Swindon on Monday as part of their ongoing investigation into the poisoning.
British Prime Minister Theresa May said she was appalled and shocked by Sturgess's death and the interior minister, Sajid Javid, said the "desperately sad news only strengthens our resolve to find out exactly what has happened".
Police are continuing to hunt for a contaminated container which they believe was handled by the pair.