Larter will work closely with Tequila's management team including Paul Hackett and CEO Tim Bonnet, with a brief to grow the agency's client portfolio.
Cahill, who is to be the managing director of the newly launched Tequila Ireland, has been with partner group TBWA for more than six years, having worked with TBWA Amsterdam before joining Tequila\London as managing partner.
Larter has 15 years' experience working in integrated marketing. Most recently, she was board business director and partnership director at Claydon Heeley Jones Mason before she left to have a baby. At Claydon Heeley she was responsible for overseeing a portfolio of clients such as Royal Mail and British Airports Authority. Before that Larter was managing director of Grey Direct, now Joshua.
Bonnet said: "Gina's strong industry track record and innovative leadership skills make her a powerful addition to our management team."
Larter takes up her post immediately.
The Omnicom-owned Tequila network has 44 offices across 31 countries. It is partnered worldwide with TBWA. Its clients include O2, The One Account, the Army and Barclays.
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