Police must launch a permanent blitz against human traffickers following a series of high-profile cases of women forced to work as prostitutes, Conservatives said.

David Davis, the Shadow Home Secretary, unveiled the policies two years after police rescued 19 women in a raid on Cuddles massage parlour, in Bearwood, Birmingham.

The Home Office last night said it had already toughened up the law and was working closely with other European nations to fight traffickers.

The Birmingham case helped reveal the extent of the problem after a Hungarian couple were jailed for a total of five years and eight months by Wolverhampton Crown Court.

West Midlands Police launch a major campaign last October to target gangs luring young women into the region to sell them into prostitution.

Operation Pentameter II focused on criminal gangs preying on Eastern European women who thought they were coming to the region to work in bars. It followed a similar crackdown two years ago.

Mr Davis yesterday unveiled Conservative proposals to ensure more traffickers were prosecuted and to offer more support to the victims of human trafficking.

He said police should make Operation Pentameter a permanent measure so that the problem was treated as a priority all year round.

He also said the number of places at safe houses should be increased, and rules should be changed to allow support groups to help children aged 16 to 18.

Currently, projects for women who have been forced into prostitution may be forced to turn away young victims because they are not allowed to help under-18s.

The proposals were backed by Birmingham MP and Conservative Shadow Cabinet Minister Andrew Mitchell (Con Sutton Coldfield).

He said: "This is a deeply distressing and worrying problem, and unfortunately we have seen one of the most serious cases here in Birmingham.

"We must ensure fighting human trafficking is a top priority for police, and that the victims of these appalling crimes are given all the support possible."

Mr Davis said: "It is quite incredible that this is happening.

"The simple truth is that the legal responsibility of social services to take children into care is to protect them, and patently this is not happening."

He added: "The idea of a girl of 15 from Estonia going to one of these centres and being turned away makes me want to cry."

Mr Davis called on the Government to introduce a treaty which will allow alleged victims to stay in Britain for up to 30 days.

The Council of Europe's Convention on Action Against Human Trafficking has been signed by ministers but has not yet been ratified.

He said: "The Government signed the European Convention on Human Trafficking amidst great fanfare last year.

"But, a year on, the Government doesn't even have a plan or timetable for ratification."

A Home Office spokesman said: "The Government is determined to tackle the misery of human trafficking.

"We have a comprehensive end-to-end strategy, set out in the UK Action Plan launched in March 2007. We have introduced wide-ranging anti-trafficking laws resulting in a number of successful convictions, and have put in place the Serious Organised Crime Agency and the UK Human Trafficking Centre.

"We have signed the Council of Europe Convention and will ratify as soon as we can.

We are determined to get the arrangements right before we ratify.

"This involves widespread consultation and primary and secondary legislation.

"This is not unique to the UK. "Most other EU countries are in a similar position."