Trading Standards told me their anti-cold calling campaign is already off to a great start, with hundreds of thousands of people downloading the "WARNING" notice to put in their windows.
TV presenter Gloria Hunniford is spearheading the campaign, and she has met many people who have been conned by unscrupulous tradespeople.
As she explained to me, the worst case she has come across is a man who lost more than half a million pounds, after trusting conmen who persuaded him to have a huge amount of unnecessary work done to his house.
Thankfully, the criminals are now behind bars, but the victim only got back a fraction of the money stolen from him.
The conmen gained the trust of the elderly couple by offering condolences for their daughter and son-in-law. They had photograpahs in the room of both of them.
There were also photos of Harold's mum receiving a telegram from the Queen on her 100th birthday and a picture of the ship he served on during the Second World War - a mine sweeper that took part on D-Day.
The conmen then started doing a bit of work on the wall and said there was a problem with a bush near the house; the roots were affecting the foundations and urgently needed to be removed. They then insisted on being paid £3000 in cash.
Second World War veteran Harold Trace, 86 and his wife Joyce, 82, from Ashford in Surrey, were scammed out of £3,000 by conmen who took advantage of their vulnerability - their daughter had died of cancer the month before, their son-in-law the year before, leaving their granddaughter orphaned.
The conmen used the death of the couple's daughter to gain their trust. Three men arrived at their house in September last year. They claimed to be from the company that had painted their house over 20 years ago; they wanted to check everything was ok at no charge.
They left saying everything was fine and Harold gave them a £5 tip for their time. Shortly afterwards they returned to say they had noticed the wall was unstable and urgently needed work. Harold and Joyce welcomed them back into the house and offered them tea and biscuits.
The theme of this year's National Consumer Week is 'cold calling - don't buy it!'
The Trading Standards Institute is calling on people to get tough on cold calling which it says is not in decline and vulnerable people are being targeted.
It has created stickers to put on your door to tell rogue traders to go away. If they refuse to go away it then becomes a criminal offence. People are then encouraged to phone the police.