An investigation is under way to find out what caused a boiler to leak after a family were taken to hospital.

The house containing an extended family of 12 was evacuated in Tolworth Rise North on Sunday night.

Three adults and two teenagers, who complained of feelings of nausea and dizziness, were taken to Kingston Hospital leaving firefighters to ventilate the home.

Firefighters at the scene identified a boiler used to heat the water in the flat, as the source of the fumes.

Building control officers at Kingston Council were looking into the incident after it was revealed work going on at the house may have caused the boiler to omit the potentially deadly fumes.

Ashraf Malik called for an ambulance when his wife complained of feeling unwell and then collapsed on the sofa in the front room at about 9.30pm on Sunday.

An ambulance took her to St George’s Hospital, Tooting, but it was not until Mr Malik and then his youngster daughter started to complain of similar symptoms that staff realised they might have been poisoned.

Mr Malik, 51, a father-of-four who works for British Airways, said the family were recovering, but were still in shock after what happened.

He said: “I couldn’t breathe and when they tried to ask me what was wrong it was very hard to speak, I was quite frightened.

“Then when my little girl’s legs gave away after my wife had collapsed I didn’t know what was going on.

“It is a terrible shock and was very traumatising. I’m just happy my family were able to make it out OK.”

Mr Malik said a builder had been working near the boiler, but said it had not been moved and insisted that he had planning permission for an extension to the property.

A council spokesman said: “The incident is under investigation by building control.

“This investigation will seek to establish the cause of the incident and whether all of the building works at the property follow planning and building control regulations.”

The family are well known among the Pakistani and Muslim community and were believed to be related to Andar Malik, one of the founders of Kingston Mosque.

According to a source at the mosque the family were now living with a relative in Kingston and said to be recovering well.