The data, which is billed as the most extensive ever piece of research into the size of the ‘informal eating out' market, was produced by industry analysts, Allegra Strategies.

On average UK consumers spend £12.75 a week on eating out and 7.7bn informal meals are eaten out a year in the UK which works out as 128 meals for every person in the UK.

However the value of eating out is expected to be £40.3bn in 2009 - a fall of 0.5% from last year. This is the first time there has been a decline since the emergence of the market in the 1960s. In 2009, one in nine meals were eaten away from home, down from one in eight in 2008.

The report notes that growth is expected to return in 2010 with the market growing again to £47.5 bn by 2014 due to rising trends in affluence, mobility, more older customers with a youthful attitude and the 2012 Olympics which is being held in London.

Steve Easterbrook, chief executive of McDonald's UK, said: ‘For the first time in 40 years, the recession is taking a bite out of a market which is traditionally resilient to downturns. The British public is becoming ever more discerning about the way they spend their money, and this is starting to affect the performance of the sector.'

Steve Gotham, project director, Allegra Strategies, added: ‘There is a myth that, with relatively low transaction sizes, the informal eating out sector is recession proof, but this report shows that, while some companies continue to do well, many are suffering.'