Ex-pat's don't get other benefits UK Gov "are committed to ensuring economic security for people at every stage of their life" by supplementary benefits (NOT given to ex-pats). Saying "leaving EU will not affect up-rating your UK State Pension only until April 2022 "is terrifying pensioners.
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Brits retiring abroad for better weather and lower prices often did so for health and economic reasons.
Accepting that they would forgo most of the support for pensioners on state pension, including services for the elderly and the NHS hospitals. They left, relying on the annual increase to survive inflation. Using savings from the EU contribution, you can protect ex-pats reliant on UK state pension, who left before Brexit.