But speaking at the annual Radio Academy Festival in Birmingham, Mr Bannister said Mr Evans had helped attract young listeners to the station's breakfast show since joining earlier this year.
"There is evidence that Chris is attracting younger listeners to Radio 1 and that was one of the major targets for the network."
Evans joined Radio 1 in April to help reverse a chronic ratings decline which earlier this year saw its audience fall below 11 million for the first time in its history. Leaked figures for April suggested that the station's fortunes were beginning to change, with around 500,000 listeners reportedly returning.
Much of the publicity accompanying Evans' arrival centred on his fee, rumoured to be worth pounds 750,000 to his independent production company Ginger, which makes the show.
Mr Bannister refused to be drawn on the precise figure yesterday. "Figures that have been bandied around are wildly exaggerated. Radio 1 will not be more expensive to the licence payer this year than it was last year. The money will be found by us being more efficient."
n The BBC'S board of governors is expected today to decide whether the two new satellite services outside of the UK, BBC World and BBC Prime, which already take advertising should be allowed to seek sponsorship for their programmes.Reuse content