Around 15 million people who experienced poor public services in the last two years did not register an official complaint, a study has found.

Half believed it would not make a difference and one in five feared they would be treated differently for complaining.

The report by Citizens Advice found just 4.2 million of the 19.2 million people in England who had a poor experience with public services such as their local council, GP or the DVLA made a formal complaint.

The charity helped 117,000 people with problems relating to public services last year, up 6% from 2014. Queries about making a complaint have rocketed by 63% in the last three years and accounted for one in ten of those inquiries.

Chief executive Gillian Guy, said: ‘Problems people have with public services too often go unreported. People are not making a complaint because they find it daunting, are not convinced it will change anything or are worried about the consequences.

‘There needs to be a clear and consistent route to registering complaints formally about public services.

‘Public service providers, from the DVLA to local authorities, can learn valuable lessons about how they can improve their service and deal with emerging problems from the complaints people make. They should also look at more informal ways to take on board feedback such as through social media.’

Local Government Ombudsman, Dr Jane Martin, said: ‘I welcome the research from Citizens Advice, which highlights how complaints can be a force for good.

‘Councils and care providers need to make it as easy as possible for people to raise concerns. By using the insight gained when things have gone wrong, services can be improved for the benefit of everyone.

‘People should feel comfortable in coming forward with their complaint, confident in the knowledge that there is an independent ombudsman to look at their case if it remains unresolved.’