City’s chamber of commerce says that half of firms have been attacked.
Small and medium businesses in London are especially vulnerable to cyber crime, according to a new report by the city’s Chamber of Commerce and Industry (LCCI).
The study found that half of London firms have experience a cyber attack at some point, with many companies "largely oblivious" to advanced tactics used by hackers to steal private information.
Colin Stanbridge, chief executive of LCCI, said: "Small and medium-sized enterprises (SMEs) often have very limited resources that can allocate to cyber security so the Government and Mayor of London must be more targeted in their approach to reaching smaller firms with helpful information, and focus on providing easy-to-adopt online security solutions.
"Unless more is done to help smaller firms understand and put in place at least basic security measures, the reputation of London as a major global centre for business is vulnerable."
Smaller firms are often targeted as a means of accessing the assets of larger ones because of the common weakness of their security, in a what is known as a "watering hole" attack.
Government figures claim that cybercrime costs firms at least £21bn a year in the UK, with severe attacks on small firms costing between £65,000 and £115,000, having doubled since last year.
City of London police commander Steve Head said that SMEs should report attacks to Action Fraud, which is preparing for bulk reporting of cyber attacks in the near future.
He said: "Only by having the full picture of how cyber crime is targeting industry can law enforcement and government put in place the resources and measures required to combat what has a quickly become a massive threat to the sustainability and profitability of companies operating up and down the land."