David Cameron's Conservatives are in crisis after being beaten into third place by the United Kingdom Independence Party (Ukip) in one of the party's top General Election target seats.

In the wake of the disastrous Eastleigh by-election result, Tory MPs privately warned the Prime Minister could face a leadership challenge unless he started to turn around his party's fortunes.

Mr Cameron defiantly insisted that the poll won by the Liberal Democrats in what even leader Nick Clegg described as the "worst possible" circumstances happens to mid-term governments and insisted he would not lead his party to the right.

However, Tory MPs attacked the leadership both publicly and behind the scenes, warning their leader was out of the touch with the grassroots and that support for Ukip could not be dismissed simply as part of a protest vote.

They pointed to recent issues, including Mr Cameron's support for gay marriage, which they said were driving traditional Conservative voters away.

And they openly questioned how the party can win the 2015 General Election if it could not take Eastleigh, in its top 40 target seats, from a LibDem party mired in scandal.

The LibDems won the seat, albeit with a much reduced majority, after its former Energy Secretary Chris Huhne resigned last month for lying about his ex-wife taking his speeding penalty points and in the middle of allegations that former chief executive Lord Rennard sexually harassed women.

Tory MP Eleanor Laing, who said she had always been loyal during her parliamentary career, said that many Conservatives felt hurt by the way they were being treated by the leadership.

She said: "They're told that they're old-fashioned and they think that they don't matter and what they stand for, and what they believe in, doesn't matter."

Mrs Laing warned many MPs were in despair about their local associations, because of the number of people who were resigning.

She said: "Inevitably, when the fortunes of the party are not as good as they ought to be, then there is some disquiet."

Tory MP Stewart Jackson claimed the Coalition Government's gay marriage plans, similar to those announced by the SNP administration, had driven away many voters.

Privately some warned that the Conservative leader could face a challenge to his position if the party's troubles continued.

There were also questions about the party's choice of candidate, Maria Hutchings.

She was speedily whipped away from the waiting press pack after the result, following a campaign in which the Tories were accused of refusing to allow her to speak in public after a series of gaffes in which she was dubbed a British Sarah Palin.

Ed Miliband also faced pressure from his own MPs after the party was pushed into fourth, in a seat where they have in the past come second, by Ukip's success.

The party ran a lacklustre campaign, seemingly wanting to shy away from stealing LibDem votes for risk of letting the Tories in by default.

However, Labour MP Austin Mitchell questioned how the move tallied with the party's message that it represented all of the party's much-mentioned "One Nation" and warned Labour had to do more to appeal to voters in the south of England.

Despite his party's good result, Ukip Leader Nigel Farage was forced to reject criticism that he had "bottled it" and that his party could have had its first MP if he had stood himself instead of putting forward a candidate with no national profile.

The victorious LibDem candidate Mike Thornton won with 13,342 votes, a majority of 1771 over Ukip's Diane James,

Ms Hutchings polled 10,559 votes, while Labour's John O'Farrell received 4,088 votes.

EASTLEIGH

LD hold

Mike Thornton (LD) 13,342 (32.06%, -14.48%)

Diane James (UKIP) 11,571 (27.80%, +24.20%)

Maria Hutchings (C) 10,559 (25.37%, -13.96%)

John O'Farrell (Lab) 4,088 (9.82%, +0.22%)

Danny Stupple (Ind) 768 (1.85%, +1.56%)

Dr Iain Maclennan (NHA) 392 (0.94%)

Ray Hall (Beer) 235 (0.56%)

Kevin Milburn (Christian) 163 (0.39%)

Howling Laud Hope (Loony) 136 (0.33%)

Jim Duggan (Peace) 128 (0.31%)

David Bishop (Elvis) 72 (0.17%)

Michael Walters (Eng Dem) 70 (0.17%, -0.30%)

Daz Procter (TUSC) 62 (0.15%)

Colin Bex (Wessex Reg) 30 (0.07%)

LD maj 1,771 (4.26%)

19.34% swing LD to UKIP

Electorate 79,004; Turnout 41,616 (52.68%, -16.61%)

2010: LD maj 3,864 (7.20%) - Turnout 53,650 (69.28%)

Huhne (LD) 24,966 (46.53%); Hutchings (C) 21,102 (39.33%);

Barraclough (Lab) 5,153 (9.60%); Finch (UKIP) 1,933 (3.60%); Pewsey

(Eng Dem) 249 (0.46%); Stone (Ind) 154 (0.29%); Low (Nat Lib) 93

(0.17%)