The economy grew by just 0.8 per cent in the three months to the end of September, official figures have shown.
Most analysts had predicted that it would have expanded by an even lower 0.4 per cent, in the third quarter.
Construction grew by four per cent while manufacturing was up by one per cent.
The gross domestic product (GDP) figures released by the Office for National Statistics (ONS) showed that the economy grew by 1.4 per cent in the previous quarter.
Howard Archer of global Insight said: "While the data suggests that the economy had more momentum than thought in the third quarter, it does not fundamentally change our view that growth will be markedly slower going forward as economic activity is pressurized by major fiscal tightening increasingly kicking in, persistently tight credit conditions, slower global growth and significant constraints on consumers."