KPMG has dismissed the prospect of a cyber-terrorism induced financial meltdown as "the stuff of Hollywood", following a warning from the head of the City of London police.

Commissioner Adrian Leppard said yesterday that the financial centres of London and New York would be an attractive target for Islamic militants, such as the Islamic State, given the importance of the industry to global capitalism.

Stephen Bonner, partner at KPMG, a professional services firm, said: "Financial meltdown from cyber attack currently remains the stuff of Hollywood, but we still need to think beyond current threats and look to a future which is likely to include more political extremism by increasingly cyber-savvy groups.

"It may yet turn out to be the next ‘y2k’ bug – lacking the visceral impact of explosions or hijacked aircraft – but with the potential to create much concern and heated debate."

The City of London and New York will be sending permanent staff to one another’s offices to encourage greater co-operation between the cities as part of preparation against cyber-terrorism.

This follows the second Waking Shark exercise in London last November, which highlighted a communication problem between financial firms due to a lack of central institution for exchanging information on cyber-threats.

Bonner added that the interconnectedness of global finance meant that such a cyber-attack would have implications for world business, and as such "would require a community response".

"More information about threats is shared than ever before but it’s still not enough," he said. "Questions remain about whether organisations really understand how reliant they are on each other."