Marketing experts have warned that McDonald's plan to open hotels and American-style diners could backfire horribly.

Nick Moon, head of European brand strategy at Futurebrand, said the company should stick to burgers rather than risk losing all through diversification. The fast food giant is seeking to boost revenues through its 'upmarket' McDiners and McHotels in a bid to attract new and older customers, but the proposals have not convinced brand experts.

"It's the difference between the holy grail of increasing profits and the poisoned chalice of debunking, disenfranchising the brand you had in the first place," said Moon.

Moon added that McDonald's needed to extend its brand to new franchise areas such as football grounds. He added that its diversification into hotels should have been made with an established hotelier rather than alone.

"The irony is that the stronger the brand the more difficult it is to stretch," he added. "If the hotels flop under the McDonald's name, it'll be horrific for the brand."

A more logical step for McDonald's brand extension might be into theme parks.