The viral video shows two black men fighting with a male officer. The officer's female colleague can be seen trying to help him as one of the suspects kicked the officer.
A grinning teen can be seen taking selfies as the officer wrestles with the suspect on the ground. Both officers reportedly suffered minor injuries.
Two black men aged 20 and 38, were arrested on suspicion of assaulting an officer and remain in police custody.
According to Metropolitan police spokesman, the two officers were flagged down Tuesday afternoon by a member of the public who reported an assault. The victim pointed out their attacker and officers went to speak to those involved.
"As an officer attempted to speak with those involved, one of the men resisted and a struggle ensued," the spokesman said. A number of other people became involved whilst the officer was on the ground."
Martin Rolston, from the Central East Command Unit, said: "This incident, which was captured on someone's mobile phone is truly shocking.
"My officers went to the assistance of a member of the public – who asked for their help – after stating that they had been assaulted. What happened next is a reminder of the risks our officers take whilst going about their duties.
"It is fortunate that their injuries are not more serious. There is no place for this level of violence on our streets.
"We are engaging with our community partners to discuss what happened and I hope that anyone who witnessed what happened comes forward and speaks with us."
The attack was roundly condemned. "Disgusting behavior from those who attack the officers, those who film what's going on and those who do nothing," John Apter, chairman of the Police Federation said. "They are cowards, the lot of them."
Mayor of London, Sadiq Khan, said: “I utterly condemn the disgraceful attack on two Metropolitan Police officers this afternoon. These brave officers were doing their duty and assisting the public. We owe them a debt of gratitude.”
Home Secretary Priti Patel tweeted: “Sickening, shocking & disgraceful. My thoughts are with the outstanding officers who were subject to this disgusting violent attack.”
Some critics however noted that the police waste a lot of time hounding and harassing political activist Tommy Robinson and his family, while they ignore violent criminals and rapists.