Millions of European Union migrants who are in Britain when Theresa May triggers Brexit on Wednesday will be allowed to continue to receive child benefits to send to families back home.

A document circulated among ministers by the Department for Exiting the European Union, has recommended that around three million EU migrants in the UK when the Prime Minister triggers Article 50 keep their welfare rights.

Those who arrive after Wednesday will not keep the benefits, but ministers have been warned that any attempt to withdraw them from those already here would risk Brussels taking tit-for-tat action to restrict health and pension rights of British expats in the EU.