It comes after the company announced​ that total sales rose to £676m last year, with vegetarian items seeing double-digit growth.

Avocado was the most popular ingredient, with customers eating five million last year alone.

Pret is running the pop-up store throughout June as part of its ‘Not Just for Veggies’ campaign, which is encouraging meat-eaters to try more plant-based options.

Pret CEO Clive Schlee wrote in a blog post: “We are not trying to evangelise and I won’t be forgetting that our number one selling sandwich in the UK is the chicken caesar and bacon baguette!

“Our takings in the shop will probably drop, but the pop-up will signal that Pret is serious about providing veggie and vegan options. And who knows, we might just find the next bestseller in the process.”

Veggie revolution​

Pret’s chefs are working to replace over 40 meat and fish dishes with new ingredients.

Options include dairy-free granola and coconut yoghurt; mushroom and avocado sushi salad; and a vegan red tapenade and avo superbowl with kale, avocado, roasted pepper and cherry tomato tapenade, baby plum tomatoes and mixed seeds.

The group will also launch a range of meat-free chef’s special’s from 10 May.

Schlee said: “We are doing this both to challenge our chefs to come up with delicious veggie and vegan food and to ask our customers what they think should end up on Pret’s shelves permanently.”

Research from the Vegetarian Society has found that almost three in ten people have reduced the amount of meat​ they eat in the past 12 months.

BigHospitality’s sister site MCA revealed that meat-free dishes now account for 30 per cent of new menu items at restaurants, and 19 per cent of the menus at leading pub chains.​