The prime minister wants users to have more control over the data they share online Jeff J Mitchell/Getty Images

Theresa May has promised to make Britain the world’s internet policeman and served notice that technology giants will be forced to give their customers more power over their own data.

The prime minister said that Britain “should be a leader” in regulating the internet as she outlined new details of a crackdown on how companies hold and exploit personal data. “We want the UK to be . . . the best place for a digital business to be set up and to grow but also the safest and most secure place for people to be online,” she said in an interview with The Times.

Last week’s hack attack on the NHS deepened fears of the disruptive power of technology and yesterday a defiant Julian Assange…