Fewer than 10 members of Britain First - including deputy leader Jayda Franken - showed up to picket the East London Mosque in Whitechapel.
During the "protest” which started at 11am on Tuesday, two men unfurled a Britain First banner while Franken held up a Christian cross and shouted "We want our country back”.
The trio were only there for around 20 minutes - leaving shortly after police arrived.
Franken was seen arguing with a police officer, asking him if it is "within [his] job description to come and mock a Christian who’s preaching in the street”.
She then called the police "traitors” for turning against Christians in a "Christian country”.
She claimed it was "[her] duty as a Christian to save fallen souls from the damned”.
Men were filming the incident and laughing at the group - though some indistinct shouting can be heard off camera.
The caption on a video of the incident posted on YouTube, said: "Another hapless Britain First protest outside the East London Mosque today.
"Last time they entered the mosque and trampled over the carpets, before running off when a traffic warden approached their illegally parked vehicle.”
A spokesman for the mosque, Salman Farsi, told the Evening Standard: "It was a bit worrying for us because we had a school group on a tour inside the mosque.
"There was a moment when they were provoking passers-by and someone confronted them and spat in their direction, so mosque staff stepped in to move them along."
Source: The Independent