More than 9,000 people have been targeted by “sextortion” scammers threatening to reveal intimate images of their victims in the first weeks of the lockdown, new figures reveal.

It comes as police are warning of an increase in online fraud as cyber criminals look to exploit those spending more time at home during the Covid-19 crisis.

Emails are sent to victims demanding thousands of pounds in Bitcoin to stop videos of them taken on their webcams, while visiting adult websites, being shared with friends and family members.

Action Fraud said it had received 9,473 reports of the scam this month, with 200 coming in the last week.

The emails, which contain a genuine password from one of the victim’s accounts, begin: “I require your complete attention for the upcoming 24 hrs, or I may make sure you that you live out of guilt for the rest of your lifetime.”

They falsely claim to have access to a victim’s social media accounts and mobile phone contacts, as well video footage filmed after taking control of their webcams.

The messages read: “I have the full recording. If, perhaps you think I am playing around, simply reply proof and I will be forwarding the particular recording randomly to eight people you know.”

Pauline Smith, the head of Action Fraud, said the “sextortion” scam is a type of “phishing attack”, where fraudsters try to trick people into paying a ransom.

She said: “The messages can look particularly convincing because they often include the recipient’s genuine password.

“The criminals sending these emails are ruthless, unscrupulous individuals who don’t care about the impact of their actions on victims. They seek to exploit people’s emotions - shaming and scaring the recipient enough that they make a payment.

“If you receive an email that threatens you, your family, or your property in any way, and asks you to make a Bitcoin payment, don’t take the bait.”

The National Cyber Security Centre revealed it shut down more than 80 online scams on the first day of its new email reporting service. The Suspicious Email Reporting Service was launched as part of a cyber security awareness campaign to combat the recent trend of scams offering services related to coronavirus.