If a free parcel arrives on your doorstep, it might not ring any alarm bells.

Eastern Daily Press: Stephen Maunder, from Norfolk County Council trading standards, is warning about a new 'brushing' scam. Picture: James BassStephen Maunder, from Norfolk County Council trading standards, is warning about a new 'brushing' scam. Picture: James Bass

But trading standards officers in Norfolk are warning people to be vigilant for unexpected parcels, which may be part of a new scam known as 'brushing'.

Originating in America in the last 12 to 18 months, reports are starting to emerge around the UK, with one made in Norfolk and a handful in Suffolk.

What exactly is brushing?

Eastern Daily Press: A worker picks orders at the Amazon UK Fulfilment Centre in Peterborough, Cambridgeshire. PRESS ASSOCIATION Photo. Picture date: Tuesday November 25, 2014. Photo credit should read: Chris Radburn/PA WireA worker picks orders at the Amazon UK Fulfilment Centre in Peterborough, Cambridgeshire. PRESS ASSOCIATION Photo. Picture date: Tuesday November 25, 2014. Photo credit should read: Chris Radburn/PA Wire (Image: PA Wire)

Stephen Maunder, a community protection officer for Norfolk County Council trading standards, said: 'The premise of the scam is that you will receive a parcel. Generally, it seems to revolve around an Amazon facilitated delivery, but often with places on Amazon Marketplace.'

The marketplace is similar to eBay, in that, while it is owned by Amazon, it allows third party sellers to sell new or used items alongside the website's usual offerings.

And the scam centres around reviews on those sellers' listings.

Mr Maunder said: 'In the same way as eBay, a lot of that kind of commerce relies heavily on feedback. So your position and chance of making sales is improved by the feedback that you receive.

Eastern Daily Press: A worker tapes shut a parcel in the Amazon fulfilment centre in Peterborough Cambridgeshire as it prepares for Cyber Monday. PRESS ASSOCIATION Photo. Picture date: Tuesday November 28, 2013. Amazon predict that the busiest day for online shopping this year will fall on Monday 2nd December. Photo credit should read: Chris Radburn/PA WireA worker tapes shut a parcel in the Amazon fulfilment centre in Peterborough Cambridgeshire as it prepares for Cyber Monday. PRESS ASSOCIATION Photo. Picture date: Tuesday November 28, 2013. Amazon predict that the busiest day for online shopping this year will fall on Monday 2nd December. Photo credit should read: Chris Radburn/PA Wire (Image: PA Wire)

'In the past, online sellers have done a lot to get fake feedback, people creating their own reviews and so on.'

But Amazon has worked equally hard to root out fake reviews, now prioritising sellers with verified reviews - generally those linked to online purchases. Generally, the scam involves quite low value items - hair grips or sunglasses, for example - of which there are many sellers, meaning they have to work harder to appear in online searches.

I've got a free parcel then - why does it matter?

Mr Maunder said someone would get hold of your details, initially an email address, to either log into a dormant account, or create a new one. The nature of the scam means they will also know your address.

He said the sellers may have obtained your information legitimately - perhaps you have ticked, or not ticked, a check box on a previous website allowing them to 'share' your information.

'It may have from that, where people have put their information in somewhere in good faith,' he said. 'There is such a large black market of data, and it can be gathered in a lot of ways.'

The sellers can then register an account, or potentially take control of an old account that is dormant.

In the scam, the sellers pay for it themselves, so no money is lost.

Once it is delivered, it enables them to write a positive 'verified' review, with the website unaware that it is not a legitimate order.

'I think this is where people have said 'well what's the problem', a parcel has been ordered, they've paid for it and it's been delivered,' Mr Maunder said.

'But it comes back to the fact that somebody is using your personal data. Depending on how they are harvesting that data they have possibly got other information, potentially financial, as well.'

And as a consumer, he said, it means fake, misleading reviews are being posted on products you may want to buy.

So what do I do if I think it's happening to me?

Mr Maunder said the first step was an obvious one - be mindful of where you share you information.

'In high street stores you often hear people giving out so much information because a person has asked them for it,' he said. 'It's important that when someone asks you for information to think whether that person really needs it, and why.'

Secondly, he said it was wise to change passwords if you had suspicions you were being targeted.

'The first time we were aware of it in Norfolk was late last year,' he said. 'But for a lot of people it might never cross their mind to report it. They might think it was a mistake, and it might be that it's only when they contact the supplier, or start getting multiple parcels a day, that they think to call.'

If you have been locked out of an account, contact the company to let them know.

You can also contact Royal Mail and report any scam mail, letter or parcel you receive.

And to report something to Norfolk's trading standards, contact Citizens Advice consumer service on 03454 04 05 06, or use the online enquiry form on Norfolk County Council's website.