Covid-19 track and trace: what can UK learn from countries that got it right?

Pledge of world-beating' system will have to look to likes of South Korea and Germany

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Boris Johnson's insistence that the UK will be able to roll out a world-beating" coronavirus test, track and trace regime by 1 June has inevitably drawn comparisons with countries around the world that have already set up effective Covid-19 tracing programmes.

It has also raised questions about timing, as some experts insist a system would have been more useful at the beginning of the pandemic.