BBC reprimands DJ Sara Cox for backing Kerry in presidential race

The radio 1 DJ Sara Cox has been chastised by the BBC for breaking its rules on impartiality by expressing support on her show for the United States presidential candidate Senator John Kerry.

A listener complained after Cox endorsed comments by Chris Martin, the lead singer of the rock band Coldplay, who voiced his support for Mr Kerry at the Grammy awards in February. In its quarterly bulletin, the BBC's programme complaints unit said: "In unscripted comments intended to express enthusiasm for a British success ... Sara Cox went beyond reporting Chris Martin's remarks and, in effect, endorsed them."

The radio station's management reminded Cox, who recently swapped the Radio 1 breakfast show for Chris Moyles's afternoon "drive time" slot, of "the importance of maintaining due impartiality on controversial matters".

Mark Byford, the BBC's acting director general, said it had missed its target for responding to complaints. Between January and March, the unit received 363 complaints, but only responded to 28 per cent of these within its target period of 20 days. In the past year only 35.5 per cent of complaints received replies within the allotted time. Mr Byford said: "It reflects the difficulties the unit has been working under."