Lots of British sitcoms are recorded in front of a studio audience. It is not normal practice to add a laughter track in later. In fact on at least one US show - M.A.S.H. - the laughter track was removed when shown here.
The thing I always noticed was how in Dr. Who and Monty Python, there would be abrupt shifts between video (for indoor shots) and film (for outdoor shots). Why?
Both of these shows were made in the 70’s when good , portable video cameras were not available. Hence the use of film cameras instead.
I’d have to disagree with this. PAL has higher definition (more lines in the picture), and I think it looks a lot crisper than US television.
As far as colour goes, I find the US pictures to look garish, so I guess it stands to reason that British TV would look washed out to American eyes. It all depends on what you’re used to. I remember 1980s American shows looked appalling when showed on British TV - everyone had bright orange faces.
Maybe because two of the main networks don’t show any commercials, so imported American shows don’t take up the full 30 minutes or one hour. For example, 24 only lasts 45 minutes, The Simpsons 22 minutes.
I wanted to add that casdave’s explaination was very good and answered a lot of queries I had as well.