The UK business recorded revenue of €286 million; an 18.7 per cent year-on-year increase.
Organic growth for the UK was 4.4 per cent in 2015, described by the company as a strong performance against a high baseline.
Havas’ organic growth was 5.1 per cent last year globally; with Asia-Pacific/Africa showing the fastest growth at 7 per cent and Latin America the slowest at 1.3 per cent.
Havas UK reported revenue of €81 million for the final quarter of 2015 – up 14.1 per cent on the same period in 2014.
Last year Havas made about €80 million in acquisitions as the holding company aims to strengthen its digital, technology and creativity capabilities. Among these is FullSix, the independent digital shop headquartered in Paris, with 600 staff based in the UK, continental Europe and the US.
Yannick Bolloré said: "These results are the outcome of a highly effective strategy centered on collaboration and integration among all the Group's areas of expertise, to provide our clients with an efficient and innovative service that seamlessly combines creative, media and digital.
"I would especially like to thank our clients for their loyalty and trust. I would also like to thank our 18,000 talents all over the world who have made such good results possible."