Salisbury poisoning: 2,300 objects recovered and 4,000 hours of CCTV footage examined

Counter-terrorism police chief Deputy Assistant Commissioner Dean Haydon released the new details as he said officers were still following “a number of lines of inquiry”.

He said a number of leads had come from members of the public, as he thanked the people of Salisbury for their patience during the “extremely challenging investigation”.

The Skripals were found unconscious on a bench in the Wiltshire city on 4 March after being poisoned with the military nerve agent Novichok.

They were taken to Salisbury District Hospital along with Detective Sergeant Nick Bailey, and have all since been discharged.

Officers say 176 searches have been carried out in the city and more than 900 witness statements taken.

Also, about 14,000 vehicles and 2,500 pedestrians who were in the area at the time of the poisoning have “assessed and graded” based on significance.

Mr Hayden admitted there are certain facts that they cannot disclose currently.

“Clearly this is a very unusual case – both in its scale and complexity,” he said.

He added: “Our inquiries are focused around the people and vehicles that were in the vicinity of the Skripals’ address and leading up to where they fell ill in The Maltings (shopping area).”

There are still 100 counter-terrorism officers deployed in Salisbury.

On Monday, Wiltshire Police revealed that the investigation is expected to cost £7.5m.

The police and crime commissioner for the area, Angus Macpherson, said he will ask the Home Office to cover all costs incurred since 4 March.