In just two years, VCCP's brand marketing campaign for O2 has successfully transformed what was the struggling BT Cellnet into a major challenger brand in the UK mobile market.
Alison Hoad, convener of judges and planning partner at Campbell Doyle Dye, said: 'The O2 case tells a story of a phenomenal business transformation.
Where O2 once trailed in the telecoms market, its share price has subsequently outperformed BT, Orange and Vodafone.'
Rival operator Virgin Mobile also performed well at the awards on Monday, landing a gold for the advertising work created by Rainey Kelly Campbell Roalfe/Y&R.
The campaign has aided the company's growth from launch four years ago to a customer base of 4m today, with the brand activity generating £428m gross profit. Its submission showed its customer-friendly approach had enabled it to overcome the financial size of the bigger networks.
As a company, Virgin also picked up the best new client award for its Virgin Mobile, Virgin Trains and Virgin Mobile Australia entries.
Government advertising picked up two gold awards this year. The first was for the Department of Health's anti-smoking campaign 'Tobacco control'.
The DoH funded ad campaigns run by the British Heart Foundation, Cancer Research UK and NHS that were created by Euro RSCG London, Bartle Bogle Hegarty and Abbott Mead Vickers BBDO respectively. The government said the campaign has saved 10,000 lives.
Transport for London's campaign to launch the central London Congestion Charge, by TBWA\London and Fishburn Hedges, also won top honours.
The other golds were awarded to campaigns by Arla Foods-owned milk brand Cravendale, developed by DDB London and DDB Matrix; the launch of directory enquiries service The Number 118 118 by WCRS and Naked; and 'The power of dreams' campaign for Honda UK by Wieden & Kennedy London.
Honda has attributed a 28% rise in sales and £388m more revenue to the work.
DDB London and DDB Matrix and Rainey Kelly were jointly awarded the Effectiveness Agency of the Year for agencies billing above £100m. DDB London and DDB Matrix won for work across Cravendale, Volkswagen Diesel and The Guardian; Rainey Kelly won for work on Marks & Spencer, Virgin Trains and Virgin Mobile.
This year's client jury included Trinity Mirror chief executive Sly Bailey; Bernard Balderston, associate director UK media at Procter & Gamble; Royal Mail chief executive Adam Crozier; Amanda Mackenzie, vice-president of marketing for EMEA at Hewlett-Packard; and Syl Saller, director of Diageo's global brand innovation group.
The chair was held by Niall Fitzgerald, chairman of Reuters and former chairman of Unilever.