The number has almost doubled in four years.
A quarter of Britons are unconvinced that the world is warming following successive freezing winters and a series of scandals over the credibility of climate science.
The figures suggest that a growing proportion of the public do not share the belief of all three major political parties and Whitehall – that climate change is a major and urgent challenge requiring radical and expensive policies.
The survey, carried out by the Office for National Statistics, has plotted levels of acceptance of the theory of man-made global warming since 2006.
In that year it found that 87 per cent of people were at least ‘fairly convinced’ that climate change was happening.
Last year that share had dropped to 75 per cent. Numbers who say they are unconvinced went up from 12 to 23 per cent.