Ukip leader Nigel Farage and newly elected MP Douglas Carswell have joined their party's candidate Mark Reckless on the campaign trail in Rochester.
Ukip leader Nigel Farage and the party's first elected MP Douglas Carswell will hit the campaign trail again today to push to secure a second seat in Parliament.
The pair will join Carswell's fellow Tory defector Mark Reckless as he bids to regain the Kent seat of Rochester and Strood for his new party.
Mr Farage has hinted that there could be more defections to come, from the left as well as the right.
Eurosceptic Conservative MP John Baron last night refused to rule out following his former colleagues to Ukip.
He told BBC 2's Newsnight: "You should never say never in politics but the bottom line is my very strong preference is to stay within the Conservative party."
Ukip could hold the balance of power in the next Parliament, Nigel Farage has claimed following the party's Clacton by-election win.
The Ukip leader told the BBC: "We've got a chance here in a general election next year that is likely to be very tight, in an election in which no one party is likely to have a majority."
"If Ukip can keep this momentum going, we could find ourselves next May in a position where we hold the balance of power."
David Cameron earlier said that people voting for Ukip were "in danger of getting a Labour government" by stopping the Tories winning a majority.
Last night's byelection results are "significant enough for David Cameron to really regret calling Ukip 'a bunch of closet racists and fruitcakes'," ITV News Deputy Political Editor Chris Ship reports.
"It's not as if they limped over the line here in Clacton-on-Sea, they turned a 12,000 Tory majority into a 12,000 Ukip majority," he said.
"[The Conservatives] have tried everything else - they've tried changing policy, they've tried being rude about Ukip, and now they're simply saying that if you vote Ukip you get Labour."
Labour's victory in the Heywood and Middleton byelection was "a terrible win" because the vote margin had not been expected to be so small, ITV News Political Correspondent Carl Dinnen reports.
"When Ed Miliband stood on these steps a few moments ago he refused to take any questions from reporters," he said.
"Usually a leader who's just won a byelection will stand there all day telling you how wonderful they are - but he had a heck of a scare last night."
Nigel Farage's plan to ban people with HIV from migrating to the UK "is an example of the most deplorable kind of bigotry," the British HIV Association has said.
Chairman Dr David Asboe said:
His stance completely ignores the positive contribution made to society by people with HIV, and threatens to reignite the sort of discrimination and stigma attached to HIV that the vast majority of people in the UK had hoped was consigned to history. This attitude not only denigrates migrants to the UK, but also the 100,000 people currently living with HIV in the UK, and the 30,000,000 others living with HIV around the world.
Nigel Farage has hailed Ukip's performance in the Heywood and Middleton byelection as "extraordinary" and "beyond my wildest dreams".
Although the party fell 600 votes short of victory, they dramatically reduced Labour's majority, which had been a relatively comfortable 6,000.
Speaking on a walkabout in Clacton, where Douglas Carswell became Ukip's first elected MP, Mr Farage also repeated that in the north "if you vote Conservative, you get Labour" - mocking the Tories' claim that "if you vote Ukip, you get Labour".
Labour's narrow victory in the Heywood and Middleton byelection shows "the scale of disillusionment with Westminster politics", Ed Miliband has said.
Speaking alongside the new MP Liz McInnes, the Labour leader said this disillusionment had led long-time Labour voters to side with Ukip - who came second in the seat, just 600 votes behind Labour.
Newly-elected Ukip MP Douglas Carswell has said his former Conservative colleagues have been "let down by a leadership that's in politics for itself".
Asked what his message was to other Conservative MPs who were looking to him following his defection to Ukip, Carswell said, "They're let down by a party that thinks it's OK to smear good people like Mark Reckless."
"But what's really important is not whether or not MPs make the journey [to Ukip], there are tens of thousands of voters who I think are up for making the journey," he added.
Ukip leader Nigel Farage and Douglas Carswell were surrounded by journalists and photographers as they walked around Clacton following their byelection win.