West Ham are facing a Football Association (FA) investigation after a series of pitch invasions and widespread supporter unrest, with Brooking confirming that club co-owner David Sullivan was struck by a coin towards the end of the game.

The former Hammers player and manager believes the club's stewarding -- provided externally via stadium operators E20 -- needs a radical overhaul in order to avoid more unrest in the future.

"There weren't sufficient stewards and they couldn't really cope with what was sometimes going back to the bad old days of 25 years ago," Brooking told BBC Radio 5 Live's Sportsweek programme.

"The club are obviously going to have to look at things with the local police and make sure that trained stewards and police are in place -- you're almost looking at it and saying: 'This is out of control.'

"A lot of the stewards who are on duty on matchdays are not West Ham people -- they're actually stadium people and sometimes, until they get a job there, haven't had any experience dealing with football crowds.

"They were quite young and couldn't deal with the aggression they were faced with."

Brooking cut a dejected figure, sitting alone in the directors' box towards the end of the match, and revealed that Sullivan and co-owner David Gold were among those asked to leave the area for their own safety.

"I think a coin did hit David Sullivan, his glasses,'' said Brooking. "I didn't see it myself but I did have that confirmed, which was part of the reason why the people in the directors' box had to go inside, to save any more problems like that."

Stewarding issues have been a frequent problem for West Ham since their move to the London Stadium, and the latest incidents have raised fears that the club could be punished by having to play a future game behind closed doors.

West Ham -- set to jet off to Florida on Sunday for a five-day warm weather training break -- were not immediately available to comment, but Brooking issued a plea to fans to shelve their concerns for the remainder of the campaign.

"The next five home games look pretty bleak because there is no way the team will be able to play and get the points to stay up under that sort of atmosphere -- it's impossible," he said.

"That atmosphere must never be allowed to come back, otherwise the club is in serious trouble.

"The fans have to understand that and really shelve those frustrations... and allow the players to get the points to stay up."