UK factory output unexpectedly fell in May when most economists had been predicting a modest improvement as the economy began to recover from the worst slump since the Second World War.

Analysts said today's setback was a disappointment, but added that it was too early to say whether the data signal a W-shaped recovery, where the economy will dip down again before it gets better, or a plateau in a V-shaped recovery.

“Maybe we were getting a bit too optimistic or maybe we're entering a plateau,” said Brian Hilliard of Société Générale. “Both the key business surveys had been pointing to an increase in May and an upward trend for June.”

The 0.5% fall in manufacturing output in May will raise pressure on the Bank of England's monetary policy committee to raise its targets for printing money or quantitative easing when it starts its monthly meeting tomorrow.

The figures were made worse because Government statisticians revised April's figure from modest 0.2% growth in manufacturing to none at all. In part, they blamed the fact that companies are sending in their responses to their surveys later and later.

The biggest drop in output in May was a 2% fall in paper, printing and publishing, where music recordings were hard hit as more and more people switch to downloads. Machinery and equipment output fell by 1.7%.