The last group includes Kiss 100, which is already the number one station for 15-24s in London.

BBC: Digital radio's Kiss of life

One of Tarrant's rivals - Kiss 100 presenter Bam Bam - last month launched a website, ChrisTarrant.com, asking his listeners to guess when the Who Wants To Be A Millionaire? presenter will leave his Capital breakfast slot.

BBC: Wogan a winner for Radio 2