Actors Maisie Smith and Jennifer Ellison, entrepreneur Calum Best, Olympic medallist Fatima Whitbread, reality TV stars Pete Wicks and Ferne McCann, ex-footballer Ashley Cain, influencer Amber Gill, dancers AJ Pand Curtis Pritchard, Olympic sprinter Dwain Chambers, taekwondo Olympic gold medallist Jade Jones, boxer Shannon Courtenay, and Paralympic high jumper Jonathan Broom-Edwards take part in a special edition of the training challenge. In the first episode, the recruits must crawl through sand in blistering 40-degree heat, before facing every desert soldier's worst nightmare - a gas attack.

S4 Ep1 75min