Michael Brown admits he is shocked that West Ham have let Grady Diangana join Premier League rivals West Brom this summer.

Speaking exclusively to Football Insider assistant editor Russell Edge, the former Leeds Unite midfielder has revealed just how impressed he was by the winger as he scored two goals on his Irons debut against Macclesfield in 2018.

The Irons confirmed last week that they had sold the 22-year-old to West Brom after his season-long loan at the Hawthorns last season.

The deal is set to cost the Baggies an initial £12million rising to £18million in add-onsFootball Insider understands.

Brown insists there will be a reason West Ham have let him leave the London Stadium ahead of the new season but admits he is surprised they have let an exciting homegrown talent head out the door.

Asked if he was shocked by Diangana’s exit, Brown told Football Insider: “Er, yes – I would say that an up and coming, emerging talent like him – I was at what might have been his debut game, against Macclesfield Town, an impressive talent.

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“Great ability, I think it’s done him really well, going to the Championship and playing week in, week out and you even see Mark Noble, he was shocked he was allowed to go.

“They must have a strategy, they must have a financial idea of why they’ve taken that and the club must obviously think it’s the right decision.”

Diangana played 17 times for West Ham’s senior side after he broke through the youth ranks in east London.

Having been sent on loan last season, he scored eight goals and contributed seven assists for West Brom.

In other West Ham news, Football Insider has delivered a big update on the Irons’ bid to sign James Tarkowski.