The latest UK media agency billings from Nielsen Media Research show WPP Group's MediaCom heading the league table for 2005.
The data reveal the shop's billings rose 18.96% year-on-year to £829.9 million ($1.45bn; €1.22bn), with satellite broadcaster BSkyB and telco T-Mobile among its highest-spending clients.
Number two in the table is WPP stablemate MindShare, coming from last year's fifth place, with a billings rise of 31.95% thanks to Unilever, whose account it won in 2004.
Carat, part of the Aegis empire, took third spot in the list, up from fourth rank in 2004, while Starcom UK Group, owned by Publicis, slipped from second to fourth. ZenithOptimedia, also Publicis-owned, fell two places to fifth.
Data sourced from mandmeurope.com; additional content by WARC staff