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It washed up across the North Sea where it was found by a volunteer cleaning up a Norwegian island - who then dispatched a postcard to the delighted sender to let her know.

Crucially, the letter writer seemed to know this - something only the sender could have known.

It means customers don't have to wait at home for a delivery - the sender or parcel business emails or texts a code to unlock the locker.

The Welsh government said it would be up to the sender to release the letter.

Consumers should also avoid engaging with unsolicited messages from unknown senders.