Less than two weeks after securing promotion to the Premiership, West Bromwich are being ravaged by internal strife which threatens to sabotage their first top-flight campaign for 16 years.

The Albion chairman, Paul Thompson, resigned on Tuesday night and yesterday he launched an extraordinary verbal tirade against the club's manager, Gary Megson, on the official website.

Megson's own future has been brought into question after he complained of intolerable boardroom interference in what he considered to be team affairs.

There is already speculation that Megson could follow the example of the Brighton manager, Peter Taylor, and walk out on a club having just steered them to promotion.

However, Thompson's decision to quit, which he says was made in the best interests of the club, could well serve to end Megson's period of uncertainty.

Thompson said: "Clearly it is not helpful to the club at this point in time if you have a situation where the manager doesn't want to work with the chairman. In those circumstances, from my viewpoint, the right thing to do for the club is to allow the manager to see if he can work with a different chairman as soon as we can recruit one.

"Hopefully Gary will then be happy to return to working as part of a team. I think Gary is in a very strong position at the minute and he wants to do it his way."

However, Thompson said that Megson's insistence on playing a more prominent role in the financial side of the club – while seeking to retain total control of the playing side – was hampering Albion's plans. "The current position where five people can't sit in the same room to talk about players is just complete nonsense. I haven't been allowed by Gary to sit down with [the assistant manager] Frank Burrows for a meeting for two years. There is no logic in it whatsoever, but it is the way that Gary wants to operate at this football club and it is just nonsense."

Thompson was in charge at Albion for 28 months and is adamant that his tight control of the purse strings enabled the club to build for a sensible and healthy future. However, he says that the club must remember the lessons of the past if that rosy future is to be maintained.

"[Megson] now wishes to dictate to the club which players we should buy," Thompson added. "Unfortunately that was the way the club was run for 15 years before I became chairman, and that policy of allowing managers to dictate which players we should buy has repeatedly failed.

"It's important that a manager is prepared to work as part of a team alongside the chairman, chief executive and directors, and Gary is no longer prepared to work as part of a team with me. In those circumstances, I can't take the club forward any further."

Megson has been asked to attend a board meeting at The Hawthorns next Tuesday to discuss potential signings.

West Bromwich earned promotion to the top flight as runners-up to the First Division champions Manchester City, pipping their fierce Midlands rivals Wolves. However, with little money to spend, the club are already strong favourites with many to make a swift return to the Nationwide League.