An academic has claimed that there is really very little difference between a cheap and cheerful Mr Whippy and a bowl of rich and indulgent Häagen-Dazs , despite what the ad makers say. "Yes, there is variation in terms of quality due to the range of ingredients - top ice creams use fresh cream and eggs and the cheaper ones use milk powder - and of course there are differences in flavours [… But] there's a limit to which they can differ from each other," insists Peter Barham, a physicist at Bristol University.