Companies will be forced to hand over to their customers the information they hold about their buying patterns to enable them to shop around and get better deals.
Energy and mobile phone companies, banks and credit card firms will have to provide the data held about customers' transactions when they request them. If they fail to do so voluntarily, the Government will pass legislation making it compulsory – and extend the "consumer power" plan to other businesses.
The "midata" programme, to be announced today, is designed to correct the imbalance under which companies build up a mountain of data about people's purchasing habits and lifestyles to help them sell their products – but consumers are often left in the dark about the practice.
Twenty energy, finance and telecoms firms have already signed up to the scheme. Ministers hope millions of people will be able to view their data on computers or mobile phones and work out quickly which energy or phone tariff suits them better; compare the prices or look at the health benefits of their food consumption across all stores; and be told about new films, music or shows tailored to their previous choices and personal taste.
The programme, drawn up by the Department for Business, Innovation and Skill, was based on evidence from Downing Street's Behavioural Insights Team, which has been dubbed the "nudge unit".
Jo Swinson, the Liberal Democrat Consumer Affairs Minister, said: "This is all about putting power into the hands of consumers. Many businesses reap huge commercial benefits from the information they gather from consumers' daily spending patterns.
"Why shouldn't consumers also benefit from this by having access to their own data to enable them to make better choices?"
She added: "It's great when your energy provider tells you how much gas or electricity you're using at any point in the year, or when phone companies tell you which one of their tariffs suits you best. But it's even better when consumers can use that information to get better-value-for-money deals or adjust their lifestyles. This is just one of many ways 'midata' can help, as businesses increasingly recognise sharing data as a means to deliver a better service for their customers."
Richard Lloyd, executive director of the consumer group Which?, said: "The 'midata' programme can help put consumers in the driving seat of the information revolution while boosting competition and supporting growth among companies that provide the best products and services."
He added: "We're pleased to see the Government putting in place measures to give people the right to data that companies hold on them.
"Giving consumers more power with their personal data will help them make better use of their money, and that's not only good for customer-friendly businesses, but good for growth in the economy."
The Government said it would consult business before making the programme compulsory.