Adam Boulton and guests discuss the new NHS contact-tracing app that's being trialled in the Isle of Wight to help slow the spread of Covid-19.But the decision to go it alone has attracted criticism from privacy campaigners and tech experts who argue it will not be as effective as incorporating the global footprint of Apple and Google.In this week's All Out Politics podcast, the panel debate whether the centralised system envisaged by NHSX is more favourable than the decentralised option. And how receptive are the public to the idea of more data gathering?Joining Adam to examine the issues are the author of 'Big Data: Does Size Matter?' Timandra Harkness, the visiting professor of forecasting and innovation at London South Bank University, James Woodhuysen - and Sky's Technology correspondent Rowland Manthorpe.