From mid-October 2013, Arena’s 150 staff, led by chief executive Pedro Avery, will relocate to the fourth floor of St Martin’s Lane office, which already houses 300 Havas Media staff.
Taking inspiration from the formation of the ‘Havas Village’, housing all group creative and media operations created in Paris last year, Mark Craze, chief executive of Havas Media Group UK, called the move "a tangible next step on our exciting journey".
He added: "The aim, as Dominique Delport has already told Campaign, is to one day have a single office in London.
"With all the consolidation taking place within the industry, we are never going to be the biggest, but the focus internally is all about being the smartest. Having key people located together will play a key part of that process when it comes to best practice and being agile. Change faster is how the French like to call it."
There will no staff changes to the two agencies following the move, with Havas Media UK being led by chief executive Paul Frampton and Arena led by Avery.
Both will continue to report to Craze, who stressed each would retain their distinct and separate brands but, together, will also offer clients a strengthened data and content focused proposition. He added that in future there will also be closer collaboration with the other group agencies Cake, Arnold KLP and Havas Sports & Entertainment.
Havas Media Group's data vision will be delivered through specialist services including Artemis, and Elisa DBi (Digital Business Intelligence) the specialist data consultancy recently acquired by Havas Media Group.
However, to enable the move to happen, some staff will be moving out of St Martin’s Lane into Arena’s former office, including Craze himself. He said the biggest gains will be made in having the investment teams, data offerings and programmatic buying teams together.
There were no such obvious benefits to having himself, along with IT, and the finance divisions in the mix while space was at such a premium.
Craze added: "The new structure is designed to be client-centric, smart and agile and has proved phenomenally successful in the French market. This is a massively exciting time for the brave and the bold to seize new and exciting opportunities."
Arena moved into its current Tottenham Court Road office from Marshall Street in W1F after being acquired by Havas in December 2007.