Watson replaces Leicester’s Will Hurrell, who went with England to last year’s tournament in Japan, as he is ruled out of the five match tournament with a back injury.

The 18-year-old Exiles starlet has featured for England at Under-16 and Under-18 levels and scored twice in two appearances in the Under-20 RBS 6 Nations, crossing the whitewash on his debut against Scotland and in the 47-33 win over France.

"Will's been struggling with a stress fracture in his back since February," said head coach Mark Mapletoft. "We'd wanted to give him as much time as possible to get it right but he's had a couple of setbacks and the change had to be made.

"Marcus came into the side and did well in the last two games of the Six Nations. He was unlucky to miss out on a place in the squad in the first place. He's back in now and I'm sure he'll take his opportunity."

England, second seeds behind New Zealand, will play hosts Argentina, Ireland and France in their pool.

The squad includes five survivors from last year’s tournament in leading points scorer Tom Homer, of London Irish, the Harlequins pair of Rory Clegg and Joe Marler, Saracens’ Jamie George and Gloucester’s Shaun Knight.

England U20 Junior World Championship squad

Forwards
Arthur Ellis (London Wasps), Jamie George (Saracens), Jamie Gibson (London Irish), Alex Gray (Newcastle Falcons), Calum Green (Leicester Tigers), Lee Imiolek (Sale Sharks), Shaun Knight (Gloucester Rugby), George Kruis (Saracens), Joe Marler (Harlequins), Charlie Matthews (Harlequins), Jacob Rowan (Leeds Carnegie), Mako Vunipola (Bristol Rugby), Will Welch (Newcastle Falcons), Jackson Wray (Saracens)

Backs
Freddie Burns (Gloucester Rugby), Tom Casson (Harlequins), Tom Catterick (Newcastle Falcons), Rory Clegg (Harlequins), Charlie Davies (Stade Francais), Andrew Forsyth (Leicester Tigers), Sam Harrison (Leicester Tigers), Tom Homer (London Irish), Jonny May (Gloucester Rugby), Sam Smith (Harlequins), Christian Wade (London Wasps), Marcus Watson (London Irish)