Jonnie Robinson, Curator, English accents and dialects, British Library Sound Archive, writes:
These speakers use of a number of features that are typical of a traditional Dorset accent. Above all, they're all rhotic speaker - that is they pronounce the sound after a vowel, at one time a feature of speech throughout the UK and indeed until relatively recently still widely heard across much of southern England. Nowadays, however, it's increasingly restricted to the West Country and the far South-West of England, a small area of Lancashire and most of Scotland and Ireland. Listen carefully to the way they pronounce the words part, more, Dorchester, purse, younger, one or two and girls. Listen also to the vowel sounds they use on words in the following two sets: aside, night, like and fights and now, down, about and amount.
Perhaps the most salient feature of pronunciation in Great Britain is the distinction between speakers in the north who generally pronounce the vowel in words such as bath, grass and plant with a short vowel – rather like the vowel in the word cat - and those in the south, who use a long vowel for these words - rather like the sound you are asked to produce when a doctor examines your throat. In the West Country, however, you frequently hear speakers using a vowel that is a sort of half-way house between the two extremes. Listen to the way Michael pronounces this vowel sound in the word dances.
An extremely subtle distinction between speakers from different parts of the country is the way in which high frequency phrases such as it is, it is not, it was and it was not are articulated in connected speech. Many speakers in the West Country, perhaps particularly older ones, omit the first vowel in the phrases it is and it was as Michael does here in the statement it was all people you knew - often represented as 'twas in dialect literature. Also listen carefully to the way he says there wasn't never any, well, you used to get one or two fights - the <s> in the word wasn't is pronounced almost like a sound. This was again at one time common among speakers in many parts of the West Country on the phrases isn't and wasn't, but is perhaps nowadays only associated with older speakers.