A group of English Defence League supporters clashed with youths outside a magistrates court as their founder faced charges inside.
EDL leader Stephen Lennon was attending West London Magistrates Court in Hammersmith.
He was facing charges over an Armistice Day poppy-burning stunt by Islamic extremists.
About 65 people were involved in the fracas. The Met's Territorial Support Group made five arrests.
The disorder has since largely died down, with officers directing those involved away from the area.
A Metropolitan Police spokesman said: "We were called at about 16.40 to reports of a disturbance.
"Officers attended to deal with two groups fighting.
"Five people have been arrested for various public order offences."
Stephen Lennon also goes by the pseudonym Tommy Robinson.
In March a Muslim extremist was found guilty of burning poppies at a protest in west London on Armistice Day.
Emdadur Choudhury, 26, of Spitalfields, east London, was fined £50 for offences under the Public Order Act.