As for Luton itself, and my first visit there, it would be unfair to comment. All we really saw was the Arndale Centre (blerr) and the Art Deco town hall, which is rather lovely. Here's the story from Wikipedia:
The original town hall was destroyed in 1919 during Peace Day celebrations at the end of World War I. Local people including many ex-servicemen were unhappy with unemployment and had been refused the use of a local park to hold celebratory events. They stormed the town hall setting it alight. A replacement building was completed in 1936.
One of the trainees (who didn't look old enough) told me that the rioters broke into a shop and dragged out a piano, and then sang songs as they torched the old town hall. One of the forgotten moments of radical British history, and presumably very worrying at a time when the threat of Bolshevism was taken very seriously. There's a good article about it here.