The award, which was judged by Marketing’s editorial team, was introduced this year to recognise the "best of the best" across the 13 category winners.
Judges for the media agency of the year said PHD, which also won the category last year, was "innovative and forward thinking".
In the advertising category VCCP triumphed after achieving runner-up status last year
"At a time when clients are placing effectiveness at the top of their priority list, the campaign results for each of VCCP's brands are very impressive. This is an agency that proves great advertising equals effective advertising," was the judges' verdict.
Work Club was named as the best digital agency, while Lida, which topped off a strong year by winning the £24m O2 account, finally clinched the top spot in the direct category, after being pipped to the post for the last two years.
The Red Consultancy was crowned PR agency of the year after impressing judges with its "good old-fashioned sales metrics", which demonstrated the positive effect of its work on its clients' business.
Elsewhere, Publicis Blueprint marked an incredible turnaround by winning the customer publishing category.
This year, the awards had an added emphasis on effectiveness to reflect the growing need for marketers to demonstrate the ROI of their work.
Grand Prix and Media - PHD
Advertising – VCCP
Direct – Lida
Digital – Work Club
Sponsorship – Fast Track
Branding – Interbrand
Customer publishing – Publicis Blueprint
Contact centres – CPM
Market research – Brainjuicer
PR – The Red Consultancy
Experiential – TRO
Field marketing – CPM
Promotional marketing – Haygarth