Ten per cent (5.8 million) of people provided unpaid care for someone with an illness of disability.
Over a third (37 per cent, 2.1 million) of those people were giving 20 or more hours care a week.
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The man was taken early this morning to a south London police station where he remains in custody.
The Chancellor faces tough talks to build a Government while also dealing with the challenge from a resurgent far right.
Watch John McDonnell's speech at Labour Party conference 2017 live as he speaks to Brighton the audience from 12.15pm.