A joint electronic research project, which was initiated by Rajar, will be trialled in London using a panel of 500 people, but results will not be made public.

Electronic measurement for radio is due to be implemented next year, according to Rajar’s future planning document, Roadmap for Change, but UK sources say Rajar has not yet decided which device to use.

It is believed Arbitron’s portable peoplemeter will be used in the new trial as it is the only developed device that is stable enough to meet Rajar’s requirements.