A mother and daughter killed by suspected "gas poisoning" while on a boating holiday in the Lake District have been named by police.

Cumbria Police confirmed that the two people who died at Windermere on Monday were Kelly Webster, 36, and her 10-year-old daughter, Lauren Thornton, both from Leyland in Lancashire.

A police spokesman said: "Cumbria Police were alerted to Lake Windermere by the ambulance service after it was reported that three people on a privately-owned boat were having serious breathing difficulties.

"On arrival, Mrs Webster and her daughter, Lauren, were being treated by paramedics and were airlifted to Royal Lancaster Infirmary, where they tragically died. A man, 39, from Leyland, who was also on the boat, remains in Royal Lancaster Infirmary receiving treatment."

The spokesman added: "Police are not treating the deaths as suspicious, and it is suspected that the deaths were caused by some form of gas poisoning. Inquiries continue to be conducted by officers on behalf of the coroner."

The alarm was raised at around 4pm on Monday when police and an ambulance were called to the private boat.

The incident, at a jetty near Bowness, was witnessed by businessman and television personality Duncan Bannatyne, who remarked on the police and ambulance activity to his followers on Twitter. The Dragons' Den star later posted a photograph of the scene, saying: "Tragic accident over there I am afraid."

There was no answer at what is believed to be Ms Webster's home address in Leyland.

A number of floral tributes had been left outside the semi-detached house. One note read: "RIP Kelly and Lauren. Gone but never forgotten. Sarah X", while another said: "Kelly and Lauren, Thinking of you and your family at such a sad time. Love always Louise Waring."

At another family address in Leyland, a woman answered the door and said she did not wish to comment. A man, who described himself as a family friend, later left the house and said: "They are too upset to talk at the moment."