Britain's beer-brewing support ships

Have British warships ever had legal beer-production facilities?

Yes; Britain operated beer-producing ships during the Second World War.

British beer-producing ships during the Second World War provided a counterpart to American ice-cream factory ships. Both examples concern supplying crews at sea. The suggested exchanges between the two services and the enthusiasm of escorting crews are banter, rather than a documented account of a particular trade or escort operation.