McDonald’s bought a 33% stake in Pret in 2001 which helped the chain expand beyond the UK.

However, in 2008 Pret was sold to private equity firm Bridgepoint with Pret’s management team retaining a 33% stake.

Lewis PR has been appointed to handle Pret’s corporate, consumer and social media communications to push the sandwich chain’s “strong customer loyalty, innovative products and team personalities”.

The firm is planning a year-long programme of marketing and communications to build the brand’s global reach ahead of its 25th birthday.

PR strategy will focus on the chain’s commitment to give away unsold food to homeless charities at the end of every day. The chain claims it gave away more than 1.7 million meals to the homeless in 2010.

Alex Dower, Pret brand and strategy director, says: “Pret is embarking on its next stage of expansion and we wanted an agency that could help us grow globally.”

Pret operates 240 outlets across the UK, USA and Hong Kong.