Ben Shephard's sons certainly know how to have fun in the sun! The Good Morning Britain star took to Instagram on Tuesday to share a brilliant video showing Sam, 13, and Jack, 15, mud sliding with their friends in a marsh.MORE: Tipping Point and GMB host Ben Shephard's family home revealed In the caption, Ben wrote: "As the great lyric goes 'Mud mud glorious mud nothing quite like it for cooling the blood!' While we've been sweating in the studio filming here's my boys with their great mates