Toxic fumes from a barbecue could have poisoned a six-year-old girl at a New Forest campsite, police have revealed.

Isabelle Harris, from Gosport, was on an Easter camping trip at Holmsley campsite with her family when she began “fitting and not breathing” in her tent.

Frantic attempts were made by her parents and paramedics to revive her, but she suffered a cardiac arrest on the way to hospital and died soon afterwards.

The youngster and her parents had a barbecue at the campsite on Thursday afternoon, just hours before her death.

A post mortem on Friday failed to reveal an exact cause of death.

But the Daily Echo understands that officers are now awaiting the results of toxicology tests, which would reveal if she died from carbon monoxide poisoning.

Isabelle’s parents, Lee Harris, 30, and Tracey Harris, 40, were arrested on suspicion of murder but were released without charge later the same day.

Police revealed they were treating the death as a "tragic incident”.

A police source said: "The post mortem did not reveal an exact cause of death so we are now waiting for the results of toxicology tests.

"The results may take a few weeks but they would show if the girl suffered from carbon monoxide poisoning, which is one line of enquiry.

"We know the family had a barbecue on Thursday afternoon before the girl died and people have died after breathing in the fumes before.

"We do not know how close to the tent the barbecue was."

Mr and Mrs Harris have released a heartfelt tribute to their daughter, saying she was a “really special girl”.

In a police statement, they said: “We are all absolutely devastated about what has happened.

“No words are strong enough to describe how we feel at the moment.

“Isabelle was our whole world; everything we ever did was for her.

“She was a really special girl and this is a huge loss to everyone who knew her.

“The police investigation has concluded and a file will be passed to the coroner.

“We really don’t want to discuss this further. We want to find out why this happened and we would like to leave the police to get on with this.

“We would like to thank the owners of the camp site for their assistance and apologise to other campers on the site who were there to enjoy their bank holiday weekend.

“We would like to give special thanks to the first responders and paramedics who treated Isabelle at the camp site.

“Our thanks also go to Hampshire Constabulary.

“We thank them for the way they have treated us, being as open and honest as they can. We also appreciate their ongoing support and have no issues with their actions.”