Apple's chief executive Tim Cook has called for the US to introduce a national privacy law, attacking a 'shadow economy' in which people's personal data is bought and sold without their knowledge. Mr Cook said companies should have to collect as little data as possible and make it easy for people to delete the information that is held about them. It is the latest attempt from Apple to position itself as the steward of consumers' privacy, and to draw a line between itself and companies such as Facebook and Google. Mr Cook said that people need to 'win back their right to privacy' and that companies that sell data should have to register with the Federal Trade Commission, the US consumer watchdog. 'I and others are calling on the US Congress to pass comprehensive federal privacy legislation - a landmark package of reforms that protect and empower the consumer,' Mr Cook wrote inTime Magazine. He singled out 'data brokers', companies that purchase, bundle up and sell data on individuals, such as credit reference agencies, saying that most people were unaware of how companies transact in their data. 'Right now, all of these secondary markets for your information exist in a shadow economy that's largely unchecked. Let's be clear: you never signed up for that,' Mr Cook wrote. The US does not have a national equivalent to the UK's Data Protection Act or the European privacy legislation, GDPR. Facebook, Amazon and Google have all said they would support a law, but failed to put forward any concrete proposals. Mr Cook said companies should aim to minimise the amount of data they collect and make it easier for people to delete or correct it. Mr Cook has played up Apple's privacy credentials in recent months, as sales of its iPhones stumble and as Google and Facebook have been embroiled in repeated data controversies. Its privacy commitment has come under scrutiny, since Apple receives billions of dollars a year from Google to be the default search engine on the iPhone. Mr Cook has defended the deal, saying the company has built in controls to limit how much users can be tracked. Click here to read full news..