Hi Phil, I'm sure Bellamy was following the example of traditional singers in breaking up the rhythm, but I suspect that - like everything else he did - he chose to do it in spades. Also bear in mind that, as Ewan MacColl pointed out, ‘it is a mistake to lump folk singers together as if they were soldiers on parade’ - meaning that traditional singers didn't all do the same thing. Walter Pardon, who you mention, often sang with an irregular metre, others less so. Sometimes the 'irregularity' was just a matter of pausing for breath, for a bit longer than you would if you were singing over a 4:4 guitar rhythm.

Learning songs from a highly stylised revivalist like Peter is fraught with difficulty, and I'm quite sure he'd have told you off for it, and ordered you to go and listen to the people that he'd listened to instead. If you learn songs from any revival singer, especially one as idiosyncratic as Peter, then my advice would be to try to forget completely the way they did it, and start again from scratch with words and tune, then try to put something of yourself into it. Dick is right that Peter didn't sound like any traditional singer, but you can hear elements of all kinds of traditional styles in his singing - it's just that his timbre, pitching, decoration and exaggerated conversational style are very individual.

If you've listened to enough traditional singers and are learning a song from a book to perform unaccompanied (i.e. with no imposed rhythm from an instrument), then it should be possible to bring some of that irregular style into your performance. It's actually very liberating.