Owner Guochuan Lai vetoed a move for Chris Wilder, a favourite of the board, then David Wagner ruled himself out despite holding extensive talks before an unexpected move to Swiss side Young Boys.

Former Albion player and coach Michael Appleton has also reportedly withdrawn from the race to focus on his project as Lincoln manager.

To add to the uncertainty, sporting director Luke Dowling left the club by mutual consent on Monday.

Xu said in a statement on the club website: "I would like to thank supporters for their patience during what has been a frustrating period for us all.

"Like all fans, I understand having a vacant head coach position can lead to uncertainty, but this is not a simple search, and we must appoint the correct person, who shares our passion for the future of the football club.

"Our aim remains the same – to earn promotion back to the Premier League as soon as possible. We will have a healthy budget in order to succeed in the Championship and, with the right person as our head coach, I believe we will have a strong opportunity to be promoted.

"As we all know, the Championship is a relentless, difficult league, but we have succeeded there before, and I am hopeful we can do so again.

"While we have not yet formally offered the job to any candidate, it is fair to state we have faced setbacks and, with that in mind, I do not think it is wise to set a precise deadline by which an appointment will be made.

"As I have referenced already, the quality of our next head coach is of far greater importance than how soon they can be appointed. We are working tirelessly behind the scenes to identify the right person and we will share this with you as soon as an appointment has been made."

On Dowling, Xu said: "I would like to thank Luke for his work behind the scenes at The Hawthorns during his three years with us. Luke's departure provides us with an opportunity to reassess how our football operation functions and I will provide a further update on this subject in due course."