DCI Trevor Bowles said: "We are very concerned by the level of violence that's been shown in the most recent offences. The severity of the attacks seems to be escalating.

"I have grave concerns about the stability of this individual and the threat that he poses to women who are on their own late at night and early in the morning.

"This is somebody who is prepared to use a weapon and prepared to use unprovoked violence to women."

Police are linking ten assaults on young women where they have been punched or struck on the head whilst walking or cycling in the evening or early hours of the morning, often in the St Helens/Blacklands area.

The extreme seriousness of the offences and the increasing level of unprovoked violence involved led to the case being passed from Hastings CID to Sussex Police's Major Crime Branch last week.

DCI Bowles is heading the enquiry - codenamed Operation Medium - from a specialist incident room at Eastbourne.

He explained: "Major Crime Branch deal with the most serious level of offences taking place in Sussex and traditionally that's murder, manslaughter, rape and kidnap.

"But this is such a serious level of offending, by what I believe is a single offender, that it is has been passed to us.

"Major Crime Branch has the resources and the experience to deal with more complicated linked series of crimes.

"There has been a lot of good work that's gone on in Hastings CID on this case and we are able to enhance and develop a number of lines of enquiry."

DCI Bowles appealed for help from the public in tracking down the man responsible.

"I believe there are people in Hastings who know who this person is," he said.

"Somebody will be able to put the various elements of what we know about this man together - we have the e-fits, we have a description, we know he's out late at night, he is perhaps somebody who has shown a dislike of or unprovoked violence towards women.

"I want people to put the information together in order that somebody can tell us who this is."

The man is described as white, possibly in his 20s or 30s, with brown or dark hair and of average height and build, possibly muscular.

A team of MCB detectives are working on the case using the Holmes database which is used to collate all information in major investigations.

Street meetings were also held on Sunday by neighbourhood officers to reassure local residents.

Anyone with information, however minor, should ring police on 0845 60 70 999 or Crimestoppers anonymously on 0800 555 111.