Police are investigating claims that West Ham supporters threw coins at Frank Lampard following his 200th goal for Chelsea at the weekend.
In a statement, West Ham said:
"West Ham United will be working with Chelsea to investigate the reports of missile throwing during Sunday's game at Stamford Bridge.
Any individual found to have acted in an inappropriate way will have to face the consequences of their actions, including the possibility of a ban from attending future matches."
More top news
The driver was attacked after a pedestrian - who had a child with him - walked out in front of the bus, forcing him to brake hard.
Historically Millwall fans have had the worst reputation. But now it seems Londoners have an almost equally bad impression of Chelsea.
The mayor claimed 'international despots and criminal rings' were using phoney companies to buy homes in the capital.