Dawn Sturgess died after exposure to novichok, while Charlie Rowley remains in a serious condition

Police in the UK say they believe they've found the source of the novichok nerve agent which killed a woman and left a man seriously ill.

Dawn Sturgess (44) died on Sunday after being exposed to novichok, while her partner Charlie Rowley (45) remains in a serious but stable condition in hospital.

On Wednesday, a small bottle was discovered in Amesbury in the house of Mr Rowley.

Tests have now confirmed the bottle contained novichok.

It's the same nerve agent which left former Russian spy Sergei Skripal and his daughter Yulia in a critical condition in nearby Salisbury in March.

The Skripals have since been discharged from hospital.

Work is continuing to see if the novichok from both incidents came from the same batch.

Speaking about the latest discovery, Met Police Assistant Commissioner Neil Basu said: "This is clearly a significant and positive development.

"However, we cannot guarantee that there isn’t any more of the substance left and cordons will remain in place for some considerable time."

He added: "I also appreciate there is a lot of interest in this; however, we are not in a position to disclose any further details regarding the bottle at this stage."

Investigators are now working to establish where the bottle came from and how it ended up in Mr Rowley's house.