Police have issued an alert about an online scam after receiving several reports of attempted extortion.

The ploy involves criminals posting emails to people claiming to have details about them accessing online pornography and threatening to disclose the information to friends and family unless payment is made.

Police say that the crooks often ask for payment in Bitcoin or iTunes vouchers.

Officers are urging people to delete this kind of email immediately, change their computer password and report the attempted scam to Action Fraud.

Anyone who has already fallen victim to the con is asked to call the police on 101.