Anti-BNP protestors mounted an angry demonstration on the steps of Lancashire County Hall.
Up to 100 people have been picketing outside the Preston-based county council headquarters.
Eyewitnesses said the group were trying to push back police who were guarding the entrance.
They were shouting: "Nazi scum off our streets".
Many held banners which read 'BNP is a Nazi Party' and 'Smash the BNP'.
Police say there were no arrests.
Geoff Driver was officially being named as the new leader of Lancashire County Council at the first full meeting of the new council and its cabinet, due to start at 1.30pm on Thursday.
Sharon Wilkinson, who represents Padiham and Burnley West for the BNP, was elected to the council at the elections earlier this month.
It comes after four people were arrested at a protest oustide a BNP 'victory' rally at a hotel in Blackpool on Saturday.
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