Manchester United’s players took refuge on the floor of the coach after it was held up near the stadium by chanting fans who hurled dozens of missiles and let off smoke bombs, as mounted police tried to keep order.
The bus was left with gaping holes in the protective glass covering its windows in the ugly scenes, which held up kick-off for 45 minutes on Tuesday.
The incident carried echoes of England’s notorious hooliganism of the 1980s and overshadowed the final game after 112 years at the Boleyn Ground, also known as Upton Park.
The Football Association and police both said they would investigate.
“The FA strongly condemns the unsavoury incidents this evening involving both the Manchester United team coach outside West Ham United’s Boleyn Ground and objects thrown from a section of the home support during the game,” it said.
A short video surfaced on Twitter which seemed to be filmed by midfielder Jesse Lingard and showed Manchester United’s players lying on the floor of the bus.
Lingard could be seen pulling faces at the camera and shouting “Mummy, mummy!” as players shouted, laughed and swore.
Phil Jones, Michael Carrick and Adnan Januzaj, all wearing their club suits, were seen squeezed together on the floor in the aisle between the seats.
The moment Manchester United's team bus was under attack... Video from the inside! ? pic.twitter.com/uIH1yDOyKa— CaughtOffside (@caughtoffside) May 10, 2016