LONDON— British Prime Minister Keir Starmer last week announced plans to require workers to hold a compulsory digital identity card to tackle illegal immigration.

The plan has revived a national debate, last played out two decades ago, in which fears about privacy and security run up against a government drive for greater control and efficiency.

Why is Britain doing this?

Starmer’s centre-left Labour Party is trailing in opinion polls behind Nigel Farage’s populist Reform UK party. High immigration is top of many voters’ concerns, and so far Labour’s attempts to control it have not had a big impact.

The government says digital IDs will limit access to jobs and thereby remove one of the factors drawing migrants to Britain.

Labour is trying to differentiate itself from Reform by demonstrating it is serious about immigration but with more moderate policies, said Andrew Blick, co-director of the centre for British democracy at King’s College London.

Reform has called for the mass deportation of asylum seekers and proposed scrapping the “Indefinite Leave to Remain” status which migrants can claim after five years, replacing it with a five-year renewable work visa.