As missions go, it’s a pretty tasty one. Close friends and university students Robert Ferris and Josh Cohen went on a hunt to find the best shwarma in laffa bread.

The 23-year-olds spent 48 hours tasting offerings from 11 kosher restaurants in north London. They had planned to extend the search across the UK but say they were hindered by the snow.

Mr Ferris is studying engineering at the University of Leeds while Mr Cohen is a medical student at Barts and the London School of Medicine and Dentistry. Mr Ferris (pictured right) tells People: “We eat a lot of shwarma and thought it would be an interesting study. We didn’t have exams on so we said, let’s just do it.”

They devised a rating system based on value for money, salads and meat. Additional points were awarded for readily available fried onions. The restaurants sampled were Sami’s, Disengoff, White House Express, White House, Adam’s, Solly’s, K Grill, Let’s Meat, Lemonade, Fernandez and Pitta. The winner? Sami’s in Hendon, which scored 14 out of 15. “We both agreed on Sami’s,” adds Mr Ferris. “The homemade laffa was great and the lamb was really good.” Do they not get sick of shwarma? “Not at all,” says Mr Cohen, who eats them twice a week — and more if he is with Mr Ferris.