The same kind of survey failures that have left the UK unsure about the number of people in Britain's workforce are now raising doubts about the size of its economy.

The Office for National Statistics has seen a collapse in responses to a key household questionnaire that it relies on to produce growth estimates, prompting it to take remedial action. The so-called Living Costs and Food Survey -- used in GDP readings such as those for the third quarter due to be released on Monday -- helps the British statistics agency determine people's incomes and what they're spending their money on.