The BNP has won its first seat on an English county council with a victory in Lancashire, where Labour's 20-year-rule has ended.

The far-right party took the Padiham and Burnley West ward, its principal stronghold in the north-west, where it already has four district councillors.

But the BNP took second place to the Lib Dems in the local toppling of senior Labour figures, who previously held all Burnley's seats. Four were knocked out by the Lib Dems, including two council cabinet members.

The BNP's victory in the ward, with 30% of the vote, buoyed local activists' hopes of getting the party's leader, Nick Griffin, elected as an MEP on Sunday night. He needs around 8% of the vote to take a north-west seat, against the 6.4% he polled in 2004.

The BNP also polled strongly in another of its target counties, Essex, beating Labour in 11 wards and coming second to the Conservatives in Rochford North and South. But with 35 of the county's 75 seats still to be declared, they have not won any seats.

It was the same in Lincolnshire, where, despite a focus on foreign workers in the crop-picking trade, the BNP failed to secure a breakthrough.

The new BNP county councillor in Lancashire is Sharon Wilkinson, who was born and brought up in Padiham and leads the party on Burnley district council. The rise of the group intensified following street violence between different ethnic groups in 2001.

She said: "It is absolutely wonderful for the party and gives me the opportunity to represent more people."

Kitty Ussher, the Labour MP for Burnley, speaking from the count, said: "It is disappointing. We have lost some really good county councillors who have worked very hard to serve their community.

"I think we were the victims of uncertain economic and political times nationally. Hazel Blears wore a brooch saying 'Rocking the boat'. If you are in choppy waters you don't change the captain."

Some 11% of Burnley's 65,000 voters are from ethnic minorities, mainly Pakistani and Bangladeshi communities. The county council voting turnout was around 36%, compared with the 2005 election figure of 59.54%.

The BNP fielded a record 459 county council candidates on Thursday, fighting every ward in Essex and a total of 116 in the Eastern region alone. At the last county council elections in 2005, there were 39 BNP candidates nationwide.

The BNP picked up a second county seat in Leicestershire, knocking out a Labour councillor in the Coalville ward. The party's candidate Graham partner won 1,039 votes, overtaking Conservative, Liberal Democrat and Independent challengers. The BNP's chairman called the two gains "fine results" but warned against over-optimism because of what he called "the most staggering anti-BNP campaign ever mounted by the media".

A spokesman for the anti-fascist group Searchlight said that the BNP had in general only polled significantly – 14% or more – where it was the only "non-mainstream" alternative to the major parties. Some such areas, including the party's target of Cumbria, had seen the vote fail to rise above 10%.