One of the most controversial transfer decisions that West Ham United have made in recent times was to sanction the departure of academy graduate Grady Diangana, with the highly-rated forward having joined West Bromwich Albion back in the summer of 2020.

The former England U21 international had impressed while on loan at the Baggies during the 2019/20 campaign, scoring eight goals and registering seven assists in 30 Championship games to help fire the Hawthorns outfit back into the top flight.

Such form had unsurprisingly piqued the interest of top clubs across Europe, with both Celtic and Ajax believed to have been just two of the clubs keeping tabs on the DR Congo-born starlet at the time.

Amid that rampant interest, the 5 foot 11 menace ultimately secured a return to West Brom on an £18m deal, with that move subsequently sparking outrage back at the London Stadium among supporters and players alike.

Captain Mark Noble - who has since retired - voiced his objection to the decision to allow the emerging prospect to depart, stating he was "angry" that such a talent was no longer on the Irons' books.

Fast forward two years, however, and that deal has come to look like astute business for the often maligned GSB, with the West Ham owners having managed to recoup a relatively hefty fee for a player who has since underwhelmed in his current surroundings.

While a stunning strike early in the 2020/21 campaign for the playmaker had enhanced the frustration among Hammers supporters, that proved to be Diangana's only goal involvement in that entire top-flight season, as the Midlands outfit were subsequently relegated.

The following campaign proved just as disappointing as the fleet-footed gem scored just twice and laid on only one assist in 41 league games in the second tier, with former West Brom boss Valerien Ismael having urged the £25k-per-week man to "raise the bar" with regards to his performances having failed to deliver.

Although there have been signs of encouragement for the "unbelievable talent" - as dubbed by teammate Jed Wallace - in the current campaign, he has still only scored once and registered three assists in ten league outings, doing little to leave the Hammers rueing their decision.

Such has been his decline of late, the one time £18m man is now worth just £5.4m - according to Transfermarkt - with the powers that be at West Ham having been proven right by his exit, particularly with the club having thrived in his absence, securing European qualification in each of the last two seasons.

In truth, it was a rare masterclass from GSB to let Diangana depart, bringing in a sizeable fee for a player who had cost them nothing having risen through the youth ranks.