Greggs is continuing to invest in social media with the launch of an online sandwich competition.

The Greggs Sandwich Hero app, available on the firm’s Facebook page, which has recently accumulated more than half a million ’likes’, invites online users to create a virtual concoction using up to three fillings, three salad items and sauce on a range of bread styles.

The two-week long search will then put the top 10 suggestions to a public vote, with the winning creation to be made and sold in the high street bakery chain’s UK stores.

A spokesperson for Greggs saidthe company’s fans regularly suggest ideas for innovative new products on its Facebook page: “It seemed obvious to let people put forward their ideas. It’ll be exciting to see the different combinations suggested and taste a number of interesting ideas.”

Sandwich sales currently represent around a third of Greggs’ business, with the fresh bacon breakfast roll recently becoming its best-selling sandwich.

This year, which is the 250th anniversary of the sandwich, Greggs was named the Specialist Sandwich Chain of the Year at the British Sandwich Industry Awards, beating Pret A Manger, Subway and O’Briens.