Windrush: What is the 'hostile environment' immigration policy?

The 'hostile environment' immigration policy has been blamed for the Windrush scandal.

Earlier this week, the government was forced to apologise after it emerged some children of the so-called Windrush generation had been declared illegal immigrants.

Many were threatened with deportation, denied access to NHS treatment, benefits and pensions and stripped of their jobs.

But what is the 'hostile environment' policy?

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