By noon, the station will know how successfully Vaughan, who took over on 19 April as breakfast show presenter, is settling into radio legend Chris Tarrant’s chair.
Jane Wilson, Capital’s director of corporate communications, said: “If we do really well, we’ll be allowed our moment of jubilation but we’re not basing everything on one set of figures.”
She added: “Obviously if things slip back, we’d be disappointed.
But the figures that really matter will be the ones in, say, nine months’ time.”
The Rajar survey covers the period March 22 to June 20 and includes Tarrant’s last two weeks at the mic, which the station accepts could skew this week’s result.
Mark Middlemas, a group account director at Universal McCann, said: “It’ll be a really interesting Rajar this time, but it’s important that Capital takes a long-term view. These things take time to bed in.”
Tim Bleakley, broadcast sales director at Emap Advertising, said: “A lot of people are pinning a lot on Thursday’s figures, but I think it’s best to look at it over the best part of a 12-month period.”
But he and Paul Carolan, deputy sales director of rival station Virgin, said they thought Capital would be disappointed if the Rajar figures showed that it had fallen back after all the hype over Vaughan’s take-over.