The 47-year-old victim had spent the evening drinking in pubs in Duke Bar and was set upon as she walked home.

Detectives are appealing for witnesses to the assault, which happened in Williams Road at 2-20 a.m. on Saturday.

Det. Sgt Vinny De Curtis, of Burnley CID, said: "This was a very vicious attack. She could have died. She was in a real mess and sustained nasty facial injuries. Who knows what could have happened if she had been left lying in the road. We are not just talking about one punch, we are dealing with a serious sustained attack."

The woman, who was treated at the Royal Blackburn Hospital, was seen drinking in the Victoria pub in Colne Road. Later that evening, two men saw her walking through Duke Bar and escorted her towards Briercliffe Road.

Just seconds after leaving her, opposite the Baltic Fleet pub, the two men heard screaming and ran to help the victim.

Police initially arrested four people in connection with the incident, but they have since been released without charge. Det. Insp. Derek Jones said officers were keen to speak to anyone who witnessed the assault.

The first attacker was a white woman, aged 16 to 18, with dark brown shoulder-length hair with streaks of red and purple, around 5ft. 4in. tall, wearing a green top with frilly sleeves and three-quarter length jeans.

The second offender was described as a slim white woman aged 16 to 18 with dark hair in a pony tail. She is thought to be taller than the first attacker.

The pair are thought to have left the area in a burgundy Honda Civic.

Anyone with information about the incident should ring Burnley CID on 472228 or Crimestoppers, in confidence, on 0800 555 111.