Vince Cable: Downgrading 'unlikely' to spark new credit crunch

For the first time since 1917, the United States has had its credit rating downgraded. The ratings agency, Standard and Poor's, moved the US from AAA to AA+ because of fears over the size of its debt.

The announcement comes after a week of turmoil on global stock markets, partly triggered by fears over the US economy's recovery and the eurozone crisis.

Business Secretary Vince Cable said he was confident the crisis would not spread to the UK.