WRG managing director Barry Day said: "It was a natural step as part of our planned growth this year to have an office in the capital as the London-based demand for our work has significantly increased in recent years.
"We’ve been delighted to buck the current trend and grow our business during the recession while we’ve seen other good agencies disappear."
WRG accounts for the year ended October 2009 show it boosted sales by 64%, as well as increasing its profits.
Sales rose to £28,167,987 from £17,161,763, while profit after tax came in at £535,791, up from £201,673 in 2008.
The increase is partly down to acquisitions, which included buildings firm Tectoniks Hire, according to the accounts.
Its corporate client list includes.