Re: "greatest British comedian of all time "
Too many to choose from. Barker was brilliant but there was also Tommy Handley, Max Miller, Spike Milligan, Tommy Cooper, Les Dawson, Morecambe and Wise, Peter Cook, etc. All of them have had me incapacitated with laughter in their time.
It was nice to see Peter Cook get some work from later comedians: Mr Jolly Lives Next Door is, in my view, the best of The Comic Strip films; Chris Morris' heavily ad-libbed interviews of Cook as Sir Arthur Streeb-Greebly.