In her new role, Holme will be responsible for driving new business and marketing the agency's brand.
Holme joins after a brief spell as the marketing director of Leo Burnett London, during which time the agency won accounts including Ladbrokes, Leffe and Del Monte.
She joined Burnett from HTW, where she helped win new business from Rolls-Royce and Scottish Courage. Originally from Canada, she began her advertising career in 1988 at the Bastable Hazlitt Partnership. In 1997, she joined CDP. She worked there until 2001, when she set up The Consultancy Group, and worked with agencies including Abbott Mead Vickers BBDO and InterRelations.
She moved to HTW in 2003.
Amanda Phillips, Proximity London's managing director, said: "Laura understands the importance of ensuring consistency across all communications channels, making her the ideal custodian of the Proximity London brand."