A woman who died after being exposed to the nerve agent Novichok in Wiltshire is believed to have had a “high dose” of the substance, police have said.

Mother-of-three Dawn Sturgess, 44, died on Sunday evening after falling ill in Amesbury on 30 June.

Her partner, Charlie Rowley, 45, who was also exposed to the nerve agent, remains critically ill in hospital.

Police are continuing to hunt for a contaminated container which they believe was handled by the pair.

The BBC understands Mr Rowley’s flat in Amesbury is regarded as the key location in the search. A team wearing hazmat suits is combing the small flat, working in 30-minute shifts because of the heat.