Nigel Farage today claimed a "sea-change in British politics" after elections which saw his UK Independence Party win seats on county councils across the country and secure second place in a parliamentary by-election.

With many votes yet to be counted, Ukip gained 42 county councillors in England and also beat Conservatives in the South Shields by-election, won by Labour on a reduced majority as Liberal Democrats trailed in a woeful seventh place.

Conservatives lost control of two counties - Gloucestershire, where Ukip picked up three councillors, and Lincolnshire, where the eurosceptic party won 16 seats to become the second largest grouping on the council.

After Ukip were derided by David Cameron as "fruitcakes, loonies and closet racists" and dismissed by Kenneth Clarke as "clowns", Mr Farage was today relishing what he termed a "remarkable" set of results which had "sent a shockwave through the establishment".

Touring the TV and radio studios as other party leaders laid low, the jubilant Ukip leader quipped: "Send in the clowns!"

Mr Farage said Ukip now has "every chance" of winning a House of Commons seat at the next by-election in a marginal constituency, which the party hopes will come at Portsmouth South this summer if beleaguered Lib Dem Mike Hancock is forced to stand down.

The Ukip leader told BBC News: "We have been abused by everybody, the entire establishment, and now they are shocked and stunned that we are getting over 25% of the vote everywhere we stand across the country.

"This is a real sea-change in British politics."

Conservatives were adopting a notably less hostile tone towards Ukip in the wake of last night's results, which will heighten pressure on Mr Cameron to shore up right-wing support by legislating during this Parliament for a referendum on EU membership.

Party chairman Grant Shapps said it was important for Tories to respond to the concerns of voters who defected to Ukip.

"We get it. We have heard you, we understand and we are also anxious to make progress," Mr Shapps told BBC Radio 4's Today programme.

"I think the results we have seen so far demonstrate people have concerns and reasons for voting in different directions, including Ukip, which go beyond Europe.

"We need to grasp the issues people care about. A lot needs to change and we need to change things faster."

After six overnight counts, the Tories had lost 74 county council seats and the Lib Dems were down 16. Ukip were the big winners with 42 gains, and Labour were up 26.

Conservatives retained control in Dorset, Essex, Hampshire and - narrowly - Somerset, where they lost five seats and the Liberal Democrats lost four. With counting continuing in Hertfordshire, the Tories had already won enough seats to keep hold of the council.

Having won no councillors when the seats were last contested in 2009, Ukip picked up 16 in Lincolnshire, 10 in Hampshire, nine in Essex, three in Gloucestershire and Somerset and one in Dorset.

Initial results in Staffordshire, where counting will continue later, saw some Labour gains and the Tories losing their stranglehold on Tamworth.

Labour's Norma Redfearn ousted incumbent Tory Linda Arkley in the battle to be mayor of North Tyneside.

The South Shields contest, triggered by David Miliband's decision to quit as an MP, was won by Labour's Emma Lewell-Buck with a reduced majority of 6,505.

The 24% of the vote secured by Ukip's Richard Elvin to take second place "shows that our potential with old Labour voters is very high indeed", said Mr Farage.

But it was a bad result for the Conservatives, who finished third, and a humiliation for the Liberal Democrats.

Nick Clegg's party lost its deposit after securing just 352 votes, finishing in seventh position behind an independent, an independent socialist and the BNP.

Lib Dem president Tim Farron acknowledged the result in South Shields was "shocking" for his party, but insisted it did not represent the whole picture.

He told the BBC Radio 4 Today programme: "The Westminster battlegrounds are where it is at and for the Lib Dems, South Shields is one extreme where we have got little strength on the ground and have been obliterated, and then you look at other places like Cheltenham, Taunton, Eastbourne, hopefully west London, places like West Dorset where we have got to win at the next election where we are doing extremely well.

"Most of our battles are against the Tories and against the Tories we are doing very well."

Labour's election co-ordinator Tom Watson said his party had a good night.

"We had a good result on what we have seen so far so get 50% plus of the vote in South Shields, to win back the mayor in Tyneside, to make progress in the Westminster battleground seats within counties is very good for us," said Mr Watson.

"In the Westminster battleground seats, places like Harlow, Hastings, Stevenage, Cannock, the Westminster seats we lost in 2010 and we need to win back in 2015, they are coming back to Labour in quite big numbers."

Tory backbencher John Baron, who last month delivered a letter to David Cameron signed by 100 Conservative MPs calling for referendum legislation, said the results should be a "wake up call" for the Government.

He told the BBC Radio 4 Today programme the need for at least an attempt at legislation to reinforce the Prime Minister's referendum pledge was reinforced by the poll.

Mr Baron said: "I take the view Ukip are not simply a protest party. There are a lot of people in Ukip with genuine concerns.

"If you can deliver legislation in this Parliament, or at least show serious intent that if the Conservatives get in we will definitely have an in/out referendum in 2017, then my question to anyone is why would you bother voting for Ukip?"

Business Secretary Vince Cable said the results were "obviously very disappointing" for the Liberal Democrats.

He said voters had turned to Ukip as a protest over poor economic conditions and claimed the results emphasised problems in the Conservative party.

"Unfortunately this is part of the price you pay for being in government and I think the Conservatives have had an even worse night than we did, but, nonetheless, it's not great," he told Sky News.

Mr Cable said there was already "evidence" the Tories were shifting to the right and admitted he has been "uncomfortable" in Coalition.

Asked if he would feel comfortable working with the Conservatives if they repositioned themselves further, he said: "I would feel very uncomfortable but we are in a business relationship with the Conservatives."

He added: "I've felt uncomfortable right from the beginning sometimes but that's not the issue."