WARNINGS have been issued on the dangers of fraudsters using computer takeover scams to steal money and personal details from unsuspecting victims, as data shows reported losses reached more than £16 million in the last year.

Which? the consumer organisation says it has heard from people who have lost thousands of pounds to this "convincing scam where the perpetrators phone up pretending to be tech support from a reputable tech firms such as Microsoft or BT.

READ MORE: Warnings as consumers lose £16m a year through computer takeover fraud

Here is what Which? says you should watch out for to avoid such a scam, and what to do if you suspect you have been duped.

What is a computer takeover or remote access scam?

Remote access software enables you to use one device to access another from any location by downloading a smartphone app or installing a program on your computer, then entering a password that will connect one device to another.

Although many legitimate businesses use this technology, including technical support teams, criminals also use it for nefarious purposes.

Typically, you get a phone call from someone claiming to be from a known company (commonly impersonated firms include Amazon, BT and Microsoft), in which they try to convince you to grant them access to your device, claiming they will fix a spurious problem.

Scammers may pretend to carry out tests and charge you a fee for imaginary or unnecessary services. In other cases, they may put up a fake screen and work in the background to download other software or steal passwords and other personal data.

What to do if you think you’ve given remote access to a scammer:

Switch off both the device and your wi-fi connectivity.

Speak to your banks as a matter of urgency.

Remove the relevant app from your list of recent downloads or installed programs, check for other programs that may have been installed remotely.

Change your email and online banking passwords and, where possible, enable two-factor authentication.

If you have security software, ensure it has all new and recent updates – then run a full security scan.

If you think you’ve been a victim of fraud, report it to Action Fraud online at actionfraud.police.uk or by calling 0300 123 2040.