An investigation by Ofcom, the communications watchdog, has found that Britons are being short changed by their broadband providers.

It found that millions of customers who had bought into super-fast connections were iin fact still stuck in the slow lane, registering an average connection speed of 6.2Mbps, despite speeds of  “up to” 13.8Mbps being advertised.

The reports conclusions will serve to inform an ongoing consultation currently being run by the Advertising Standards Authority into what action (if any) can be taken to curtail the practice.

At present the advertising trick is employed by many of Britain’s leading internet providers including BT, Sky and O2. Only Virgin Media was found to offer download speeds close to what it advertises, thanks to its newer cable network.

In response Ofcom argues providers should be forced to advertise the “typical speeds range” which a customer can reasonably expect top receive.

Ed Richards. Ofcoms chief exec, said: “"It is important that the rules around broadband advertising change, so that consumers are able to make more informed decisions based on the adverts they see, and that advertisers are able to communicate more clearly how their products compare to others in the market."

The consultation will report its findings within the next three months.