Rajar is to expand its research into podcast listening habits, following on from its initiative to include questions about podcasts in its quarterly survey of radio listening.

The first survey, published last week, found that nearly two million adults in Britain listen to radio programmes downloaded from the internet.

From next year, listeners who complete Rajar diaries will be asked to indicate what platform they used to listen to programmes, according to the Radiocentre's head of research, Alison Winter.