Tanya mentioned the $5,100 cab fare in a comment. The New York times has the story. The report begins:
LONDON — For the man who worked at the Ministry of Silly Walks, travel chaos across the Continent was only a modest hurdle.
John Cleese, who starred in the high-stepping sketch for Monty Python, was stranded in Oslo on Friday after appearing on a television talk show. With flights grounded by the volcanic ash over northern Europe, Mr. Cleese found another way home to London: He caught a cab.