Bostock will be watching in Belgium as England's Under-21 side face San Marino on Thursday. But he hasn't given up on a return to the fold.
He told the Mirror: "It was an honour to play for England, for the Under-16s, 17s and 19s. To captain my country at 17s was a great memory.
"I played with Wilshere, Jack Rodwell and Steven Caulker and I am really happy for them, to see that there is a route into the England senior team.
"But I am in Belgium, really enjoying my football. Ready to go again."
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