A British Jiu Jitsu champion took down an alleged sex attacker who targeted a teenage girl - and held him until the police arrived.

Ivan Skoko, 29, used his Brazilian jiu-jitsu skills to tackle an alleged attacker outside Moorgate Tube station on Friday, December 5.

Video shows a man sparring with two ‘teenaged' boys as a girl shouts "you just grabbed my a***, you weirdo"."

Ivan, who began filming on his 'phone before handing it to a bystander, stepped in and threw the man to the ground, then asked passers by to ‘call the police'.

He said: "I slowed down to see what was going on, and I heard a girl saying ‘he grabbed my a***'."

"The young guys were trying to tell him off, and he started swinging on the guys."

"I crossed the street and pressed record on my phone and said ‘can you just film the takedown?'"

"I took him down, and I said ‘call the police'."

"The police arrived and I gave my details, and everything ended up without any serious injuries to anyone."

"The police arrived very quickly - within five to ten minutes."

Ivan, who previously tackled a pickpocket on London's tube system, estimates he has fought off criminals in the capital at least 10 times.

Originally from Croatia, Ivan won gold in the men's ultra-heavy category at the British open earlier this year.

He said he wants to encourage the teenagers he helped get involved in fighting sports.

He added: "I encourage them to start training in Jiu-Jitsu or to get involved in fighting sports, so they can learn skills to fight back."

"When children and young people are involved, who cannot stand up for themselves against grown adults, I have no fear whatsoever to step in at their side as a professional."

"I think every single professional would do the same, so I'm not the only one."

"All the guys that I train with would do the same, it's all about decision-making in the moment."

"If you see the situation is escalating, you need to diffuse the situation in the safest way."

"That's what we can do, and that's what we have to do."

A City of London Police spokesperson said: "City of London Police have arrested a 26-year-old man on suspicion of sexual assault by touching and two counts of common assault."

"He has been bailed pending further investigations."