THE UK Independence Party (Ukip) claimed it had entered the political mainstream after a series of election results suggested it could cause real problems for the Conservatives at the next General Election.

Labour kept three of its safe Westminster seats following parliamentary by-elections in Rotherham, Middlesbrough and Croydon North.

But the real news was the rise of Ukip. The party came second in two of the contests, recording its best ever result in Rotherham with 21.8% of the vote, and third in the other.

The success of the party raises real concerns for the Conservatives.

The Tories face tough challenges from Ukip in key marginals at the next General Election. Just days ago the party hierarchy was forced to rule out an electoral pact with the eurosceptics in 2015, after it was suggested by one of their own MPs.

The by-elections also brought further bad news for the Liberal Democrats.

The party came only eighth in Rotherham, behind Ukip, the British National Party, Respect, the English Democrats and an Independent, losing their deposit.

It was also a dismal night for the Conservatives, who slumped to fourth in Middlesbrough and fifth in Rotherham.

The latter was triggered by the resignation of verteran Labour MP Dennis MacShane, who stood down in the wake of a highly critical report on his parliamentary expenses.

Ukip leader Nigel Farage said the results showed that the party was making big progress.

"Whichever way you look at it, Ukip is on the rise," said Mr Farage.

Speaking after her victory, the new Labour MP for Rotherham Sarah Champion urged the Government to get the town back to work.