Security tightened around the region's red light districts last night but working girls continued to walk Norwich's streets - despite being "petrified" the killer may turn his focus to the city.

Security tightened around the region's red light districts last night but working girls continued to walk Norwich's streets - despite being "petrified" the killer may turn his focus to the city.

The police presence in both Ipswich and Norwich has been stepped up significantly following the discovery of five bodies in the hunt for a serial killer and high visibility patrols were carried out in all known vice areas.

Despite the fact police have refused to rule out the possibility of sex trade regulars - and even the murderer - turning to neighbouring areas to escape the spotlight of the investigation, many girls continue to ply their trade.

Several could be seen going into a hotel in the Clarence Road area with clients. More worryingly a lone woman in her forties could be seen working in Rouen Road - defying police warnings that no woman should be out unaccompanied.

She told the EDP she had been working the streets for more than 20 years. "It's awful what's happened and we're petrified. But I've got bills to pay," she said.

"We are people just like everybody else - no woman deserves to be treated like that."

One 21-year-old, who works as Cassie, said: "I'm scared out of my mind. There's nothing to say whoever's doing this won't start targeting us - it's all the girls are talking about."

Cassie said she had been working as a prostitute in Norwich for five years. In that time she has been beaten up by two clients who refused to pay for her services. Police spoke to her several times last night and she said their presence was reassuring. But the fear which forms a daily part of her life has increased in recent days.

"You can talk to any girl and she'll tell you she's been attacked at some point, it's part of the job. But these murders are something else completely," she said.

"If I had the choice I wouldn't be out here but I'm addicted to heroin. Heroin is a physical addiction not just mental, people don't understand that."

Another woman in her thirties gave her name as Carrie and said she had been working the streets for several years. "I'm more nervous than I've ever been in my life but we're looking out for each other more than usual," she said.

"In all the years I've been out here I've never known the girls work together so closely.

"The police have been very reassuring - they've told us not to worry about being arrested just to concentrate on which clients we allow to pick us up. I'm trying to be as choosey as possible but I've got to make a living and you can never be completely safe."

Det Chief Supt Stewart Gull, who heads the enquiry for Suffolk police, said: "The police presence in Ipswich is extremely high and of course it is a possibility that women and their clients will go elsewhere. We will be liaising with neighbouring police forces on this matter."

The EDP also understands many women are choosing to frequent less well known vice areas or are working from behind closed doors. But Canon Mira Talbot, from the Magdalene Group which supports prostitutes, said this could increase the risk as women working alone are unable to look out for one another.

"No dark alleyway is safe but at least in the traditional red light areas the women can rely on their friends to watch out for them and make sure they don't disappear for too long," said Canon Talbot.

Norfolk chief constable Carole Howlett said there was not yet any evidence of the displacement of those too scared to work in Ipswich. But she said police had stepped up protection of Norwich's sex workers and echoed advice for women to be wary when out on their own at night.

She added: "We've increased patrols in our red light district and are liaising with people who support sex workers.

"We would advise sex workers not to go out alone because they are at significant risk at the moment."