Robert Symons leaves behind two young daughters

Robert Symons was stabbed through the heart in a struggle with a burglar on the ground floor of the house in Chiswick, west London, on Wednesday.

Forensic tests are being carried out on a knife found near to the 45-year-old teacher's home.

Linda Davies, who described her husband as a family man, said: "I thought we were going to grow old together."

Post-mortem tests showed Mr Symons died from a single stab wound to the heart.

He leaves behind two-year-old and five-year-old daughters.

The loss of human life in such circumstances is difficult to comprehend and all at the school are deeply saddened Head teacher Mike Hulme

"Our children are so young, I doubt that they will remember him," said Ms Davies.

"Rob's ideal was the family unit, Sunday lunches, holidays and walks. And now when the children fall down, I can hear him offering to kiss them better.

"He is going to miss the plans we made for Halloween, [their daughter] Harriet's birthday and Christmas.

"He will be missed forever."

Scotland Yard said they were hunting a man seen leaving the scene and believed the killer had previously tried to break into other houses nearby.

A spokesman said the suspect was wearing a light-coloured short sleeved shirt and may have had an accomplice.

Detectives are hunting a man seen leaving the house

Mr Symons worked as a science teacher at the Queens Park Community School, in north-west London.

Headteacher Mike Hulme said: "The loss of human life in such circumstances is difficult to comprehend and all at the school are deeply saddened.

"Our thoughts are with his family at this time of their immense grief. He will be sorely missed."

Assistant Commissioner Tarique Ghaffur described Mr Symons' death as the "brutal killing of a decent man trying to protect his own home".

He added: "We would like to reassure everybody that we are pulling out all the stops and we will be doing everything in our power to ensure that the person responsible for this is captured in the shortest possible time."