The BBC's Lisa Costello: "Restaurants across the country ground to a halt"

Long queues formed and several outlets that sold out of produce were forced to close as customers took advantage of an offer of two of the chain's hamburgers for the price of one.

Company chiefs had expected to boost their usual early January sales of half-a-million Big Macs to around 2 million, but quickly discovered they had badly underestimated the popularity of the offer as sales rocketed to more than 4 million.

A McDonald's' spokesman said that the company would be targeting supplies for restaurants that were worst affected by the rush, as angry customers were left disappointed on Monday.

Burger King competition

"Our suppliers are working extra hard to ensure that we meet demand tomorrow," he said.

Earlier in the day McDonald's confirmed that several restaurants had closed for "restocking", but insisted that it was "just a dozen or so out of our 922 UK restaurants".

The spokesman said that the chain was not anticipating further supply difficulties before the offer expires on 10 January.