BRITISH police say search teams have found over 400 items as part of the investigation into the poisoning of two Britons by the nerve agent Novichok — but searches will likely take many more weeks as officers seek further evidence.

Metropolitan Police said a day before that they had found a small bottle believed to be the source of the nerve agent that killed Dawn Sturgess and sickened her partner Charlie Rowley.

It was found at Mr Rowley’s home in the southwestern town of Amesbury.

Authorities said a “significant number” of the items found are potentially contaminated, and have been sent to laboratories for analysis.

Police are trying to figure out whether the deadly nerve agent that poisoned the pair came from the same batch used in a March attack against former Russian spy Sergei Skripal and his daughter.

Mr Rowley, 45, and Ms Sturgess, 44, collapsed at his house within hours of each other on June 30.

Sturgess died in a hospital a week ago. Mr Rowley initially was in critical condition, but has regained consciousness.

The Novichok saga began in March when Sergei and Yulia Skripal mysteriously fell ill on a park bench in Salisbury.

They were found to have been poisoned with Novichok, a lethal nerve agent produced in the Soviet Union during the Cold War. Prime Minister Theresa May blamed the Russian government for the attack, which the Kremlin has vehemently denied.

The Skripals survived and have been released from a hospital, but are in a secret protected location.

The case led the United States and other countries to expel a large number of Russian diplomats.

Public health officials say the risk to the public is low, but advised people not to pick up any strange items.