Coleman, the Heart 106.2 breakfast presenter, will be replaced by the former children's presenter Jamie Theakston at Easter.
This follows a poor showing in the fourth-quarter Rajar figures by the Chrysalis-owned Heart. It lost its second place in London to Emap's Magic 105.4, which increased its share of listening from 4.5 per cent to 6.1 per cent year on year.
Heart's share slumped from 7 per cent to 5.3 per cent while 95.8 Capital FM remained in the number-one spot in London, albeit with a dramatically reduced 6.2 per cent share. Johnny Vaughan, Capital's breakfast presenter, turned around audience declines by adding 100,000 listeners. Chrysalis is hoping that Theakston can prove more effective against Vaughan.
There was general gloom for commercial radio, which saw its total share of listening fall to 44.2 per cent, compared with 45.3 per cent a year earlier. However, its share was up on the third quarter of 2004.
A resurgent BBC, with large audience gains for Radio 1 and Radio 2, saw its share rise by 1.1 per cent to 54 per cent.
The national station talkSPORT increased its share of national listening to 1.6 per cent, compared with 1.4 per cent a year earlier. Classic FM's share also increased slightly to 4.4 per cent.
- Forum, p12.