BT has been slammed for failing to deploy fibre broadband services in London's Square Mile.
Mark Boleat, Policy Chairman of the City of London Corporation, said it is "a major concern" that businesses in the area do not have access to super-fast broadband.
Writing for City AM, he argued that "market failure of this kind is clearly unacceptable for a world-leading global financial centre".
Mr Boleat said the current provision of fibre in the Square Mile highlights the fact that poor connectivity is "not just an issue affecting rural areas" in the UK.
"The attractiveness of the City - and several other locations in London and elsewhere - is greatly disadvantaged by the lack of fast broadband connectivity at an affordable level," he added.
"Larger organisations can access expensive dedicated leased lines and there is a range of suppliers available to provide these. However, these lines are unaffordable for the 13,000 small and medium-sized enterprises and 9,000 residents based here."
As such, they are forced to remain on slower copper-based broadband connections, Mr Boleat added.
He claimed that the Square Mile is home to "innovative global businesses" and provides the market drivers for many fast-growing firms in other sectors.
Mr Boleat added that if London is to continue delivering innovative new products and services, it cannot afford to be left lagging behind its rivals "in the slow lane of the broadband superhighway".