Vaughan and co-presenter Lisa Snowdon attracted 1.32 million listeners in the final quarter of 2011, up from 1.13 million in the previous quarter and 1.08 million a year earlier, according to the latest figures from official body RAJAR.
Global Radio's Capital FM had a 2.25m average weekly reach over the three months, up nearly 15% year-on-year. The station was able to regain the top spot in London commercial stations from Magic 105.4, despite the Bauer-owned station increasing its weekly reach by 5.7% year-on-year to 2.2m listeners.
Vaughan made a shock exit from Capital on November 18, and so the RAJAR figures cover the audience for his interim replacement Greg Burns, who stood in with Snowdon before Dave Berry came in as a permanent replacement.
The Capital breakfast show from 6am to 10am was the most popular in London, easily beating Magic 105.4's Neil Fox into second place with 848,000, ahead of Kiss 100's Rickie, Melvin and Charlie, with 838,000.
Heart's breakfast duo of Jamie Theakston and Harriet Scott slipped from second to fourth in London with 814,000 listeners.
Capital had its biggest weekly reach since the first three months of 2004, when it had an audience of 2.34 million. The station also had the largest audience share in Q4 2011, at 5.9%, ahead of Magic's 5.7%.
Global Radio's Heart had a weekly reach of 1.93 million, ahead of Bauer's Kiss with 1.87m, but the Global Radio station had a lower audience share, at 4.6% against Kiss' 5.4%.
BBC London 94.9 had a weekly reach of 485,000, up 2.3% on the previous quarter. Global station Xfm saw a quarterly drop of 6.7% to 406,000.
The nationwide network of Capital stations was up 4.7% year-on-year to 7.08 million, but sister UK-wide network Heart fell 3.6% to 7.46 million.
Global founder and executive president Ashley Tabor said: "I'm delighted to see Capital performing so well in London and across the UK.
"This demonstrates the network's growing popularity and reinforces our strategy of national brands delivered locally. Congratulations to the entire team."
Elsewhere in the commercial radio sector, UTV Media's speech radio station TalkSport had a weekly reach of 3.2m, up from 3.13m in the previous quarter, and an audience share of 2.1%.
The national Smooth Radio network, owned by Guardian Media Group, had a weekly audience of 3.31m, up 7.5% year-on-year.
Absolute Radio's digital stations Absolute 80s and Absolute Radio 90s both saw strong gains, up 24.5% and 18% respectively year-on-year to 828,000 and 348,000.
Bauer's The Hits remained one of the most successful digital-only commercial stations, at 984,000 listeners a week, while Jazz FM was up 14.3% to 512,000. But NME Radio was down 20% year-on-year to 188,000.
Overall, digital radio accounted for 29.1% of all radio listening in the final quarter of 2011, up from 25% in the last three months of the previous year.
Digital audio broadcasting (DAB) radio accounted for 19.4% of all listening, while digital TV and the internet accounted for 4.5% and 3.4% respectively.
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