The family of Dawn Sturgess, who died after being exposed to the nerve agent Novichok, have paid tribute to the mother of three, calling her “a gentle soul who was generous to a fault”.

Ms Sturgess, 44, and her partner, Charlie Rowley, 45, both fell ill in Amesbury, Wiltshire, on June 30 after it is believed they handled a vessel containing the deadly substance.

On Tuesday, her family released a statement through police that said: “Dawn’s death has been devastating for us. Dawn will always be remembered by us as a gentle soul who was generous to a fault.

Amesbury incidentWiltshire Police Chief Constable Kier Pritchard (centre), outside Charlie Rowley’s house in Muggleton Road in Amesbury, Wiltshire

“She would do anything for anybody and those who knew Dawn would know that she would gladly give her last penny to somebody in need.

“She had the biggest of hearts and she will be dreadfully missed by both her immediate and wider family.”

Mr Rowley remains critically ill in hospital, and Chief Medical Officer Dame Sally Davies has warned everyone in the area not to pick up “any foreign object which could contain liquid or gel, in the interests of their own safety”.

The statement continued: “Our thoughts and prayers also go out to Charlie and his family and we wish Charlie a speedy recovery.

“We would like to take this opportunity to pass on our sincerest thanks to all of the NHS staff involved in Dawn’s care, especially the wonderful doctors and nurses at Salisbury District Hospital who we know afforded Dawn every possible chance of survival and treated her with the utmost care and dignity.

“We would also like to pass on our thanks to the police and the local community for their support.

“Finally, we would respectfully request that the media allow us the privacy to come to terms with the circumstances in which we find ourselves. We now need time and space to grieve and would also ask that people stop speculating about Dawn and what has happened.”

Amesbury incidentFlowers in Rollestone Street, Salisbury, where counter-terrorism officers are investigating after Dawn Sturgess and Charlie Rowley were exposed to the nerve agent Novichok (PA)

A massive counter-terrorism police investigation is taking place into how the couple were exposed to the chemical weapon.

The main line of inquiry is whether it is linked to the attempted murders of former Russian spy Sergei Skripal and his daughter Yulia in nearby Salisbury in March.

Assistant Commissioner Neil Basu, the country’s most senior counter-terrorism police officer, said there would need to be a forensic link to definitively prove a connection.

But Defence Secretary Gavin Williamson waded in and directly blamed Russia for committing “an attack on British soil which has seen the death of a British citizen”.

Amesbury incidentAn investigator in a chemical suit works behind screens erected in Rollestone Street, Salisbury, where Dawn Sturgess lived (PA)

Tributes have been left at Rollestone Street in Salisbury, where Ms Sturgess lived.

One read: “We did not know you, we did not know your background. We do know we feel sad about what has happened to you.

“We feel very sad that your family will not see you again. You were having a nice day out with friends and it has ended in such a tragic situation.

“We are cross about the scathing comments. We don’t like how people have been. We are sending love to your family circle and friends.”

Police in SalisburyA police officer stands in front of screens erected in Rollestone Street, Salisbury (Yui Mok/PA)

On Monday night, officers removed a car from an address in Swindon, which is some 40 miles (64km) from Salisbury. The vehicle is understood to belong to a member of the emergency services.

Wiltshire Police said members of the public should “not be alarmed” by the activity.

“Those involved have the training & expertise to safely remove the vehicle,” the force tweeted.

Public Health England said the risk to the public is low, but warned against picking up “any strange items such as needles, syringes or unusual containers”.

Central to the investigation is John Baker House, the supported-living accommodation where Ms Sturgess lived, Mr Rowley’s home in Amesbury, and Salisbury’s Queen Elizabeth Gardens, which remains cordoned off.