Downing Street is examining proposals to issue every adult in Britain with a digital ID card in a fresh attempt to tackle the country’s illegal migration crisis. Senior figures in No 10 are looking “very closely” at plans for a new “BritCard” that would be used to check on an individual’s right to live and work in Britain. The card, which would be stored on a smartphone, would be linked to government records and could also be used to check entitlements to benefits and crack down on welfare fraud.