Which? compared the nutritional content of the bars using the manufacturers' information and applied traffic light labelling to see if the levels of fat, saturated fat, sugar and salt were high, medium or low.

BBC: Cereal bars: Healthy image a myth - Which?

Some 68% of those surveyed do not think the government has been giving enough attention to enforcing labelling laws, with half of consumers not confident ingredient information is accurate.

BBC: Horsemeat scandal 'changing shoppers' habits'

This suggests that one element of the solution will be labelling when Google's in-house services -- such as maps, airline flight details or shopping comparison information -- are artificially given a higher billing than rivals.

CNN: Brussels takes tough stance on Google