British Transport Police have launched an appeal after a 34-year-old man was reportedly surrounded by a group of men and women on a Central line train.
The dispute spilled out onto platforms six and eight of Stratford Underground station where two people punched and kicked their victim.
He fell to the floor and but his attackers continued to beat him before the group ran off, detectives said.
The victim suffered cuts to his head and face in the attack around 8.30pm on March 16.
Investigating officer DC Jon Howlett said: “I am keen to speak to anyone who may have witnessed this altercation. It wasn’t particularly late in the evening and I would expect that there would have been a fair few people on the platform who may have witnessed this.
“If you were there at the time of have any information about the altercation or about the people that were involved please call us. Everyone has the right to travel on the rail network without any fear or crime or intimidation.”
Anyone with any information should contact British Transport Police on 0800 40 50 40 or text 61016 citing reference 348 13/04/2017.