The woman was attacked in Hertford Street shortly after 8.30pm last night (Thursday). The offender ran off towards Chesterton Lane. She was taken to Addenbrookes Hospital with serious facial injuries. Detective Inspector Jamie Stenton said: This was a nasty attack which appears to have been completely random. I would urge anyone who has any information or knows who is responsible to call the police as soon as possible. INFORMATION: Anyone with any information should call DI Stenton on 101 or Crimestoppers, anonymously, on 0800 555111.