Executive director at the ASI, Sam Bowman, wrote for the IBTimes on the drawbacks of preferentially buying British good and services.
Public spending should not be a jobs programme, it should be about providing specific services. Buying British, of course, really means 'buying British when a cheaper and/or better foreign alternative exists'. So given limited resources, buying British means either an inferior product or less money to spend elsewhere. That means that Buying British is a transfer from taxpayers and the users of public services to whichever manufacturers have the loudest lobbyists.