Talker Tailor said the 'boomerang' clause, to be offered in new contracts from September, aims to encourage freedom of movement within the industry, with less deterrent for employees to try something new.
The contracts will be offered to all levels below senior manager. The agency said that the initiative is an attempt to "offer wider career security for entry-level PROs" and "discourage people staying too long at [the] agency without giving something else a go".
Agency co-founder Gary Wheeldon said: "We want people to stay at our company, but it’s important for the development of our industry, and an individual’s career and happiness, that movement and sharing of ideas is encouraged.
"We believe it’s important that there is a cooling-off period between the leap and the land, and that’s why we are making this move.
"People we have spoken to have expressed concern that it may encourage people to leave our business more easily, but it is the responsibility of me, as business-owner, to show people why they should stay, not to discourage them from leaving or trying something new.
"Sometimes a new job just doesn’t work out, for various reasons; being mis-sold in interview, not seeing or meeting a whole team, the working culture etc., and people in those situations shouldn’t feel like they have no way out."
Talker Tailor was founded in 2016 by M&C Saatchi alumni Wheeldon and Steve Strickland. Its clients include Deliveroo and restaurant chains Wagamama and Burger and Lobster. The agency is shortlisted in the Small Consultancy of the Year category at the 2018 PRWeek UK Awards.