Violent clashes between rival supporters inside the London Stadium marred West Ham’s EFL Cup win over Chelsea on Wednesday.
Both Hammers and Chelsea fans threw missiles across a segregated area of the ground before breaking through security and clashing along a walkway at the top of the Sir Trevor Brooking Stand.
Police in riot gear entered the fray and managed to separate the disorder, as play in West Ham’s 2-1 victory concluded.
Sky Sports News HQ’s chief news reporter Bryan Swanson was at the game, deemed high risk by the Metropolitan Police due to the history of violence between both sets of fans.
And he said: “What this did is quite graphically illustrate that the segregation promised at this match will be questioned by the authorities, the clubs and police.
“For whatever reason, there seemed to be a slow response and that’s why it escalated so quickly.
“This was always billed a high-risk match. The police said there would be robust policing inside the stadium and West Ham were at pains to say they wanted this game to be trouble-free. They urged every supporter to be an ambassador.
“But it will raise questions about why there was that coming together of supporters on that walkway.”
There has already been violence involving West Ham supporters outside their new stadium at Stratford following the recent Premier League games against Watford and Middlesbrough.
Nine arrests have been made outside the ground since the beginning of the season, while West Ham have issued 23 banning orders for offences ranging from drinking in view of the pitch to breaking the line of segregation.