The Bank of England announced that it would pump another £50 billion into the economy to ensure continued recovery.
The move defied market expectations and put a dampener on hopes for a swift economic upturn.
The decision by the Bank to expand its programme of quantitative easing from £125 billion to £175 billion breaks the ceiling set by the Chancellor at £150 billion. It also confirmed that interest rates would remain at 0.5 per cent for a fifth consecutive month.
Ross Walker, UK economist at Royal Bank of Scotland, said: “This is a huge surprise. All the rhetoric seemed to point to not doing very much more.”