Martin G Haigh in Bristol tweets, external: Shouldn't there be an inquiry into why LibDem candidate was not on #RochesterandStrood #byelection ballot papers? Eh? 349 votes? Ohhh...

The BBC's Robin Brant tweets, external this picture of UKIP leader Nigel Farage, with the message: "He's croaky and admits he's a little rough this morning after the late count."

Labour's Douglas Alexander tells the BBC that the shadow attorney general was right to step down over her tweet, external of a picture of a house draped in England flags.

"I completely understand why friends and colleagues in England are intensely proud of the flag of St George. Emily Thornberry did the wrong thing in sending that tweet. She did the right thing in resigning."

UKIP also has its first elected member on Medway Council. Councillor Chris Irvine, who defected from the Conservative Party in September, received 2,850 votes, pushing the Tories into second place in the Peninsula Ward by-election.

He told BBC Radio Kent he switched to UKIP over the Conservative-led council's plans to build thousands of new homes at Lodge Hill.

BBC Radio 5 live tweets the question, external of whether the by-election result is a game changer - with John Pienaar saying: "The laws of political physics are being rewritten."

Douglas Alexander adds: "Of course, in truth, there are lessons for all of the main political parties given not just the result we saw last night, but the results we've seen in other recent by-elections and in the European elections earlier this year."

The Independent's Oliver Wright says, external the first-past-the-post election system means UKIP "are very unlikely to win more than four or five seats next May. In fact, its small majority in Rochester suggests that Mr Reckless may well be booted out from his seat in just a few months time".

But, he adds, if the party can succeed in taking 10-15% of the vote in the 100 or so marginal seats that will determine the next election, "then they could have a disproportionate impact on the overall result".

Alaister Jeffrey in Scotland tweets, external: No major party has ever won less than 1% of the vote in a parliamentary by-election. Until the Lib Dems in #RochesterAndStrood.

Labour's shadow foreign secretary Douglas Alexander tells BBC Breakfast: "David Cameron threw the kitchen sink at this seat but he lost. It's something of a humiliation for the prime minister."

Historian Tim Stanley writes in the Telegraph:, external "Out of this slide towards metropolitanism, only UKIP has managed to project a sense of 'getting' hard pressed voters. People don't necessarily agree with Farage or even possibly like him. But they know what he is; they understand a man like that."

BBC political correspondent Robin Brant tweets, external: @UKIP donor tells me they are targeting 40 'winnable' seats now. More details on @BBCBreakfast

Priti Patel, Conservative MP for Witham in Essex, tells the BBC's John Pienaar it is a "disappointing result" but says it was "a tight margin." She adds: "We fought a good campaign and we're proud of that."

Conservative peer Lord Ashcroft tweets, external: The Conservative Party shouldn't get too cocky about winning Rochester back at the GE. A positive rather than a negative campaign needed.

Haniya Khalid in Glasgow tweets, external: Interesting night eh, though by no means surprising-u know, except that #WhiteVanGate bombshell. #RochesterandStrood #Rochester #UKIP

Some more thoughts on the Lib Dem turnout - Christopher Hope, senior political correspondent at the Daily Telegraph, tells BBC Radio 5 live's chief political correspondent John Pienaar: "It's dreadful for them. We're seeing a cratering across the country of Lib Dem support."

Cameron Penny, in London tweets, external: #RochesterandStrood Ukip margin not enough to win at #GE2015, @UKLabour damaged, @LibDems destroyed, good night for @TheGreenParty

Marcher Lord tweets, external: I think there's something wrong with my laptop. It says the LibDems only got 349 votes in #RochesterandStrood

Image source, EPA

The leader of the Official Monster Raving Loony Party, Howling Laud Hope, seen here on the right with his party's candidate, Hairy Knorm Davidson, added a bit of colour to the election results evening. Their party pulled in 151 votes.

On the low Lib Dem vote, Professor Andrew Russell, head of politics of Manchester University, tells BBC Radio 5 live: "I think it's the lowest performance by any of the three main parties for at least two or three generations. And it's almost certainly the lowest performance in a by-election for any party of government."

Norman Smith
Assistant political editor

For the Tories, the result was not perhaps the meltdown they had feared and certainly there is no indication so far of panic, or calls for Mr Cameron to go. Senior Tories also believe they are poised to win back this seat at the general election.

For Labour, not only was their share of the vote almost halved, but there was also despair at the damaging tweet by their former shadow attorney general Emily Thornberry, seemingly mocking white van man.

As for the Lib Dems, not only were they again overhauled by the Greens but they secured a derisory 349 votes - their lowest total ever.