A MAN was fighting for his life last night after he was viciously attacked as he slept.

The 42-year-old victim is in a critical condition after suffering severe head injuries, believed to have been caused by a blunt instrument.

He was being treated in the intensive care unit last night at the James Cook University Hospital, in Middlesbrough.

The assault took place in the early hours of yesterday in a first floor bedroom of a house in Greenbank Road, Darlington.

The victim, who is not being identified, had been sleeping beside his girlfriend at the time.

The woman's son and daughter were also asleep in the house, but were not injured.

Neither the man, or his partner, had been previously aware of the attacker's presence.

The girlfriend was woken by the assault at 5am and immediately called the emergency services.

The victim was initially taken by ambulance to Darlington Memorial Hospital, but was transferred a short time later to the James Cook hospital.

It is not thought the attacker is known to the victim or his partner.

Police are appealing for witnesses, or anyone with information, to come forward.

Detective Inspector Paul Harker said: "The couple were asleep at the time of the attack and were unaware of the assailant's presence.

"Neither the girlfriend, or her son or daughter, who were also asleep at the time in separate rooms, were injured in the attack."

The attacker had two terrier dogs with him. One was described as white with brown spots and the other was a brown Yorkshire terrier cross.

He was seen running from Greenbank Road towards the Denes area of the town.

Det Insp Harker said: "The victim has suffered very serious injuries as a result of this attack.

"I would appeal to anyone with information, or anyone who saw anything suspicious at that time, to get in touch with the police."

Witnesses, or people with information, are asked to call the police on 0845 60 60 365.

People can also call Crimestoppers on 0800 555 111. Callers do not need to give their names and they could be entitled to a cash reward.