UK consumers are being warned about unscrupulous traders who will go to any lengths to swindle people out of money this Christmas.

The National Trading Standards Board (NTSB) and consumer minister Jo Swinson are warning people to watch out for the 12 most common shopping and contract scams during the festive period.

Car-clocking and fake charities are among the scams featured in the list.

Swinson said: "With so much money being spent at Christmas, people should be on the lookout for scams and ploys to dupe unsuspecting shoppers. Unfortunately, the festive spirit is not alive among rogue, dodgy and downright illegal businesses who prey on those buying gifts for friends and family."

She added: "The first thing people should do is follow the old adage - if something sounds too good to be true then it usually is. If something is not quite right or they are being pressured into buying goods or services they don't need, then they should report this to the Citizens Advice consumer helpline on 08454 04 05 06. They can ask trading standards to investigate claims and make sure consumers get a fair deal."

NTSB chairman Lord Toby Harris said: "Last year, UK adults spent an average of £592 on Christmas. At a time of year when we know consumers will be parting with hard earned money, it is imperative that they be made aware of current scams. The NTSB encourages all consumers to check the legitimacy of chosen traders before buying gifts or committing to contracts."

These are the top 12 scams to be aware of this holiday season:

1. Dangerous counterfeit Christmas gifts: The NTSB Safety at Ports teams say unsafe toys and electrical goods, which do not comply with UK safety laws, continue to enter the marketplace. These goods are not only dangerous, they can damage the economy and fund crime.

2. Charitable donations: Christmas may be the time for giving, but the NTSB and trading standards advise consumers to double-check exactly who they are giving to. Consumers should be wary of vague statements on packaging such as 'donations for work creation' or 'donations to poor children'.

3. Online free trials: New year's resolutions often involve attempts to work off mince pies and lose weight. Scammers know this and have created pop-ups offering free trials on items like weight loss supplements while disguising contracts in the fine print. After entering customers' card details to pay for post and packaging, the scammers use these hidden contracts to take regular sums of moneys from the victim's account.

4. Loan scams: Christmas time can put a strain on any budget, and unscrupulous credit businesses are cashing in on people's financial desperation. The National Scams Hub says many people have received unsolicited text messages or telephone calls from firms offering them an unsecured loan. Those who accepted were charged large, upfront fees for little or no service.

5. Doorstep crime:Bad weather is used by rogue traders to convince residents that they need unnecessary and often substandard home improvements at exorbitant prices. Consumers are advised not to deal with unsolicited and unexpected doorstep callers. Instead, they should use a trusted trader, recommended by family and friends or a part of an approved codes scheme.

6. Commodities fraud: Cold callers pester large numbers of potential victims across the UK to offer alternative market investments. Plots of land, diamonds, rare earth products, wine investments and carbon credits sold at hugely inflated prices allow the criminals to make off with their victim's savings before any suspicions are raised. By the time the victim realises the fraud, the company has vanished.

7. Computer scams: The NTSB's National Scams Hub and trading standards are warning of this simple yet dangerous scam. The victim receives a bogus call from a computer company claiming that they have been alerted by the internet provider to a serious virus attack. The scammers tell the victim the only way the problem can be fixed is to buy a special computer programme. If the owner complies, they enter their personal and financial information on to a website only to find their bank account is emptied.

8. Council tax re-branding: In a current investigation from the North-West Scambuster Team, it was discovered that less than 0.1% of claims submitted by companies claiming they can obtain council tax refunds are legitimate. The victim pays high, up-front fees to a company that does no work on their behalf. Householders can make their own application to the Valuation Office Agency themselves - for nothing.

9. Grant notices: Consumers are being warned of an email purporting to be from the Commonwealth Secretariat and HM Treasury telling them they qualify for a £1,000 grant to be paid directly into their bank accounts. This email is not an expression of yuletide goodwill, it is a scam that will put consumers at risk of fraudulent activity, and should be ignored.

10. Car clocking:Dodgy car dealers will do anything to move a motor - even adjusting the mileage on the clock to make it read fewer miles, which they use to bump up the price.

11. Security alarms:The National Scams Hub is warning consumers about a possible security alarm scam where consumers receive a cold call from a company offering to install security systems. The security system may be free or available at a nominal cost but the on-going maintenance costs are high and there is a cancellation fee.

12. Vishing: Vishing has caught a lot of people out recently - consumers have already lost £7m to this scam, according to Financial Fraud Action UK. Scammers call victims pretending to be a bank, building society or similar official and attempt to get personal information. Consumers must remember that their bank or building society will never ask for details over the phone - they already have them.