More anti-terrorism police officers are to be deployed on the London Underground and railways after the stabbing attack in Leytonstone, it has been announced.
A 56-year-old man was left with "serious" stab wounds and another person was injured during the attack in east London.
The man who carried out the attack reportedly shouted "this is for Syria!" and police have confirmed they are treating it as a terrorist incident.
BTP's Assistant Chief Constable Mark Newton said: "The safety of the travelling public remains our top priority.
"In addition to our usual specialist response teams, last week we launched Project Servator deploying even more highly visible police patrols designed to identify and deter terrorism.
"Following the incident on Saturday night, we are now deploying still more officers in this role.
"They involve both uniformed and plain-clothed officers, supported by other resources, such as armed officers, police dogs, a network of CCTV cameras, and the thousands of rail staff we work alongside."
Salim Patel, 59, who runs the station shop and saw the attack unfold, said he heard shouts and saw the attacker beat up his victim before leaving him unconscious on the station floor.
He told the Press Association: "I was just at the shop when the train arrived and people came off.
"I heard some shouting, but sometimes drunk people shout. Then I saw the guy attacking the victim, punching him so hard. The victim was screaming 'please somebody help me. Help'.
"Then the attacker started kicking him on the floor. I think the victim was unconscious, he passed out. Then the attacker took a knife out and started stabbing him as he lay on the floor.
"The victim did not shout anything. I think he was unconscious. The attacker was saying something, I couldn't hear what."
In footage of the attack, a bystander can be heard shouting: "You ain't no Muslim bruv! You're an embarrassment." The hashtag #YouaintnoMuslimbruv circulated on Twitter as Londoners rallied to distance the man, whose religion is unknown, from Islam.
Imran Patel, from Leytonstone Islamic Association, told reporters on Sunday they were "saddened" by the attack.
He added: "This was an individual who we do not know and is not a member of the congregation of Leytonstone. His motives for his actions, only he can answer for himself, he said.
"We strongly condemn any sort of violence or terrorism or any violent acts. Islam does not allow place for violence and terrorism.
Imams from Leytonstone Islamic Association condemn tube stabbing that took place in the area on Saturday https://t.co/SIKKfPR5l9— Sky News (@SkyNews) December 6, 2015
"Leytonstone is a well-integrated and multi-cultural community, who live in peace and harmony. What happened last night is totally unacceptable and we totally and strongly condemn this."
Newton added: “Britain’s railway system is an open one which we all rely on to go about our day to day lives and get to and from work. The measures we put in place make the important balance between a system with easy access for passengers and a secure one.
“Critical to this effort are the public and many thousands of rail staff to be our eyes and ears – reporting anything suspicious to us. In an emergency they should call 999, otherwise they can report anything suspicious by texting 61016 or calling the Anti-Terrorist Hotline on 0800 789 321.”