Robert Peston learns how to do the voice of Mr Punch

Earlier this year, while live on BBC Radio 4, business editor Robert Peston confessed he could not get his head round his energy bill.

Several PM listeners volunteered to explain to him how the tariffs were calculated.

One listener, Diarmuid O'Brien, came into the PM studio to teach Robert how the bills work.

The programme's editors decided to find out whether there were other subjects Robert did not know anything about, which PM listeners might be able to shed light on.

He came up with five things he wanted to learn, one of which was doing the distinctive voice for Mr Punch in a Punch and Judy show.

Robert Peston went to Brighton to learn the art of swazzling from veteran Punch performer Glyn Edwards.