By Nigel Pankhurst BBC News

A big fall in doorstep crime has followed a clampdown on "cold callers" by local councils in Britain.

A range of measures, including the setting up of more 1,000 No Cold Calling Zones, are in place to combat rogue traders, bogus callers and distraction thieves who prey on the vulnerable.

"No cold calling zones" have been set up in some areas

A 90-year-old woman with Alzheimer's disease, who was the target of a conman could have lost thousands of pounds had it happened a few years ago.

But thanks to one of the schemes now being employed by councils, trading standards officers were able to stop her being cheated.

She was saved by Warrington Borough Council's Consumer Alert Network (iCAN) initiative.

Local residents can sign up to receive alerts by phone, text or e-mail when officials get warning of a scam. Some 1,200 people in Warrington have joined the scheme so far.

In the case of the elderly woman, trading standards were able to intervene before she parted with any money after the home security con was highlighted by a neighbour.

Most of the calls we get are about cold callers and we will name and shame where we can Edwina Greenwood Warrington trading standards Crackdown cuts crime

The council says the scheme is less hit-and-miss than the old method which involved attempting to get the message out through local radio and newspapers.

Principal trading standards officer Edwina Greenwood said: "Most of the calls we get are about cold callers and we will name and shame where we can.

"It's certainly made a difference in that we are able to warn people more quickly.

"We have had more reports which is really good because if there's a doorstep con in progress we're more likely to catch them.

"We've managed to get to places and stopped work being done."

'Extremely successful'

Portsmouth is another place where the authorities are turning up the heat on the cold callers.

Five No Cold Calling Zones (NCCZ) have existed in the city for the past six months - where the council says there is effectively a blanket ban on cold calling.

The message is hammered home by lamp post notices, and in some cases the local authority can get an Asbo against particularly bad offenders.

If we can actually catch them in the act it's a lot more effective Tanya Griffiths Surrey trading standards

The council says the initiative has been "extremely successful" and well received by residents - so successful in fact that not one distraction burglary has been recorded in the zones during the six-month period.

Surrey is another of the councils to employ the use of NCCZs. There are three in the county covering 11,500 homes and more are planned.

Its trading standards also has a Rapid Action Team, comprising about a dozen council officers who can act promptly to calls from the public.

The council says the team has saved residents from handing over a total of �650,000 to conmen since it was set up in 2003.

Tanya Griffiths, of Surrey trading standards, said: "If we get a call that there are rogue traders at work at somebody's home we will get out and intervene and disrupt their activities.

"If we can actually catch them in the act it's a lot more effective."

She is in no doubt that the measures being taken against the conmen make a huge difference.