Scotland Yard warned that the scale of the problem could be far greater because such offences were “vastly under-reported”.
The Met now says it wants to encourage stronger links with private sector volunteers to combat cyber crime.
Detective Chief Inspector Gary Miles, head of the Falcon cyber fraud unit, said one of the most prolific scams was online advertising fraud offering non-existent properties for sale or rent.
Others include romance frauds — tricking people into meeting their “perfect partner” through dating websites — and identity frauds, where criminals use victims’ details from social media. Individuals and businesses also face phishing emails, ransomware attacks and more complex hacking raids.
Mr Miles said his detectives were investigating about 1,000 “volume fraud” offences and around 130 more complex cases. He added: “We are getting about 3,500 victim reports a month, but we think this is vastly under-reported.”
Last month, a gang investigated by the unit was jailed for using the bank details of hundreds of students to carry out a £2 million mobile phone fraud.
Ringleader Jonathan Boorman, 32, of Bath, and six others, including five from London, set up fraudulent phone contracts with the personal details.
Detective Chief Superintendent Mick Gallagher, head of the Met’s Organised Crime Command, today said the force already has “a lot of expertise that comes in through police volunteers”.
He added: “We have people from the banking sector working alongside my officers to investigate economic crime and we want to replicate that with cyber investigations.”
Mr Gallagher said the Met also wanted to recruit people straight from university to tackle the fraudsters. “Some criminal individuals have a high level of sophistication and are clearly very knowledgeable — our challenge is to raise our knowledge and skills above theirs to deal with them,” he said.
He added: “We do work in a clandestine way within the dark web to make sure that Londoners stay safe.”
Police are also aiming to raise awareness about how to avoid becoming a victim of cyber fraud. Mr Miles said: “We want to get people to think of their online security in the same way they think about their physical security.
“There are simple measures people can take, such as going to the Get Safe Online website and learning about how to improve passwords.”
Online fraud is now the most common crime in the UK, with more than 5.5 million offences each year.
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