TUC general secretary Brendan Barber has said the stubbornness of inflation, combined with poor wage growth, was putting real pressure on people's finances in the run up to Christmas.
Unison general secretary Dave Prentis added that the latest figures were the "lull before the storm", saying:
Big increases in energy prices are set to hit in the new year and the cost of feeding a family just keeps on going up. More than a million public sector workers have not had a pay rise for three years and the value of their take home pay just keeps on going down.
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Five people were killed and dozens more were injured after a car and knife attack in the capital on Wednesday afternoon.
Among those expected to attend the ceremony will be former US President Bill Clinton and ex-Northern Ireland first minister Peter Robinson.
Five people have been killed and 40 injured after a car and knife attack in London on Wednesday.