An elderly man with dementia was tied up and threatened in his own home for small change in a violent burglary that has left police shocked.

The 78-year-old, who has asked not to be named, opened his front door at his Carpenders Park flat last Thursday afternoon to find two young white men who said they were electricity meter readers.

However the pensioner was then grabbed, pushed back inside the Delta Gain address and bound.

The victim, who has lived in Watford for more than 20 years, said: "I opened the door as you would and they muttered something about reading my meter.

"They stood either side of me at my door and seemed normal at first.

"They then pushed me into my hallway and I then realised what was happening. I grabbed them back and the next thing I knew I was on the floor in my hallway."

The pensioner was then involved in a scuffle with the two men in which he received small injuries to his face. After being bound he fell into a cupboard underneath his stairs.

The victim, who suffers with heart problems, said he had not received bad injuries but was slightly shaken.

He said: "It was a rushed job and all happened so quickly. It was a great struggle but I wasn’t going to let go.

“All they got was the change I had in my pocket from the Co-op I had been to earlier that day.”

The intruders called the elderly man “Granddad” and demanded he handed over cash.

They later left their victim lying on the floor and went out through the front door.

It is thought they drove away in a van, parked near the flat.

The incident has left police shocked and the force is offering a £3,000 reward for information leading to the conviction of the culprits.

Detective Sergeant Mark Clawson, who is investigating the case, said officers were used to seeing distraction burglaries where vulnerable elderly people with conditions such as dementia and Alzheimer’s Disease were targeted.

However, he said this attack was unusual in its violent nature.

Detective Sergeant Clawson added: “This is a completely isolated incident and we were completely shocked.”

The police are currently hunting two suspects in relation to the burglary.

At the time they were said to be wearing dark navy blue jackets with fluorescent orange markings.

Detective Sergeant Clawson advised other elderly people in the area not to open the door to people if they were unsure who they were. He said people from gas and electricity boards made appointments before they visited at people’s doors. He added: “If you are not sure, don’t open the door.”

Anyone with information is asked to call Hertfordshire Constabulary on the 101 non-emergency telephone number.

Alternatively Crimestoppers can be called anonymously on 0800 555 111.