Screen-sharing scam cases have surged, with one victim losing more than £48,000, the City regulator has warned.

Sharing your screen without making the proper checks can “change everything in an instant”, the Financial Conduct Authority (FCA) said.

Such scams enable fraudsters to embed themselves in victims’ digital devices in order to access online banking and investment details.

Criminals are taking advantage of a growing familiarity with requests for screen sharing, the FCA warned, as the coronavirus pandemic has increased people’s reliance on video conferencing and remote platforms to work and socialise.

More than £25 million was lost to such scams between January 1 2021 and March 31 2022, with victims ranging from 18 to over 70, the FCA said.

About a quarter (26%) of 18 to 34-year-olds would agree to screensharing their online banking or investment portal with someone they had not met, research for the FCA found.

The number of screen-sharing scam cases has jumped by 86% when comparing July to December 2020 with the same period in 2021, it added.

In one case seen by the FCA, a 59-year-old woman lost £48,000 as scammers used screen-sharing software to take over her computer and access her banking history.

She was persuaded to download remote desktop software to secure an investment – and lost more than £48,000 while scammers accessed her banking details, her pension and applied for loans on her behalf.

She clicked on an advert for bitcoin and received a call from people claiming to be financial advisers.

Offering to complete the first investment for her, they asked her to download remote technology, which gave the scammers open access to all the financial details on her computer.

Her case is among thousands the FCA has received to its consumer helpline.

The FCA also surveyed 2,000 people and found just over half (51%) of would-be investors would check if a company appears on its “warning list” when deciding if an investment opportunity is legitimate.

Nine in 10 (91%) said they would never share their Pin with a stranger – but 85% of these people would not think a request by a website to use or download software was a warning sign that someone was seeking to gain illegal access to personal information on their device.

While 88% would check if their investments were offered or sold by FCA firms, 10% of these people would trust their “gut instinct” with an investment opportunity from someone they did not know without fully checking, such as ensuring the firm or the financial promotion is properly authorised.

If someone deals with an unauthorised firm, they will not be covered by the Financial Ombudsman Service or Financial Services Compensation Scheme (FSCS) if things go wrong.

Mark Steward, executive director of enforcement and market oversight at the FCA, said: “Investment scams can happen over many months, but sharing your screen without making the proper checks can change everything in an instant.

“Once scammers gain access to your screen, they have complete control.

“That means access to your sensitive banking and investment information, the freedom to browse at their leisure, and the ability to take whatever details they want.

“It can affect any investor, no matter how experienced. It’s incredibly difficult to get money back once lost in this way, but there are ways to protect yourself: don’t share your screen with anyone, as legitimate firms will not ask you to do this, and check out our Scamsmart website for advice on how to avoid being scammed.”

Here are three important questions the FCA suggests asking to protect yourself from these scams:

1. Have you checked the FCA’s Scamsmart wesbite and warning list?

This will help you to avoid being scammed and show you whether or not the firm you are dealing with is registered, or known to be suspicious.

2. Are you being asked to download anything new?

Your bank will never need to access your screen to view your information, so someone asking you to do this is a clear warning sign.

3. Have you navigated away from your banking or investment platform?

Anything that takes you away from your banking or investment app, and through a search engine, increases the risk of coming across a fraudulent number or link.