Benedict Cumberbatch’s turn in BBC Radio 4’s Rumpole Of The Bailey helped the iPlayer’s new service achieve 1 m downloads in less than a month.

The BBC, which launched the new iPlayer radio download app last month, said that BBC Radio 4 drama output has proved to be the most popular to date.

Radio 4 drama – which includes Diamonds are Forever, Silk: The Clerk’s Room and Cumberbatch’s return as Rumpole – notched up more than 81,000 combined downloads.

The BBC said it is not possible to breakdown the individual programme downloads for the Radio 4 dramas.

BBC Radio 1’s Summer Mixes proved the second most popular radio show, with 47,446 downloads, while The Archers drew 45,314, including its Omnibus edition.

“We knew from the success of our podcast service that there was a demand to download BBC radio and music content to listen to whenever they wanted to,” said Andrew Scott, general manager for radio and music at BBC Digital.

The BBC said the download service, which unlike streaming allows fans to listen to programmes and shows when they are offline, has proven to be most popular on Sundays at about 10pm as people prepare for the commute to school or work for the next week.

The corporation added that only a quarter of the top 20 downloaded programmes were previously available as podcasts, which it says proves there is significant demand for more BBC radio and music programmes offline.

“Hitting 1m downloads across the whole of BBC radio and music has far surpassed our expectations,” said Scott. “ We’re looking forward to bringing audiences even more features like this over the coming months.”