Former Sun columnist Jon Gaunt addresses the Ukip spring conference in Exeter. .

Speculation is mounting that the UK's Sun newspaper could back the right-wing party Ukip at the next election after a former columnist at the newspaper said he had joined the party, and an ex-reporter at the paper's now-defunct stablemate The News of The World confirmed he had been appointed as one of its press officers.

Columnist John Gaunt, a presenter on the TalkSport radio station owned by former Sun editor Kelvin MacKenzie, was previously a PR adviser to West Midlands police. He caused controversy after urging officers to wear T-shirts labelled "PC Pleb" as part of a campaign to force the resignation of former chief whip Andrew Mitchell after his altercation with diplomatic protection agents in Downing St last year.

Ukip leader Nigel Farage dined with Rupert Murdoch last month, emerging from the meeting to describe the News International tycoon and Sun proprietor as a "remarkable bloke". Following their meeting, the first between the two men, Murdoch posted a message on Twitter in which he said: "Farage reflecting opinion".

Ukip Deputy Leader Paul Nuttall confirmed the party had recruited Gaunt at the party's spring conference in Exeter. Last month, Ukip struck a humiliating blow to David Cameron at the Eastleigh by-election, forcing the Tories into third place.

Gaunt told the party's conference: "I believe in Ukip's education policy; in Ukip's defence policy; in Ukip's immigration policy."

He laid claim on Ukip's behalf to the much-wooed "aspirational" voter, adding the party represented "opportunity for all".

On the same day, former News of the World features editor Paul McMullan, who has defended phone hacking and other criminal press malpractice as being "in the public interest", confirmed he is a press officer for the party in Dover, where he owns a pub.

And former Tory minister Neil Hamilton revealed he had also joined Ukip, after he was seen campaigning for the party with his wife Christine in Eastleigh last month.

"I'm out and I'm proud!" said Hamilton, the former Tory MP for Tatton who was disgraced during the Cash for Questions affair in the 1990s after it was revealed he had accepted brown envelopes stuffed with cash from former Harrods owner Mohammed al Fayed.

Commentators have noted the increasingly favourable coverage for Ukip in the Sun's news reports. Recent headlines have declared: "Ukip boss slams new press law"; "Lib Dems fall behind Ukip"; "PM feels heat from Tories as rival's support hits 38 percent"; "Ukip soars to its highest poll rating after fostering scandal".

Murdoch is said to be enraged after David Cameron "blinked first" in the argument with Deputy Prime Minister Nick Clegg and Labour leader Ed Milliband over press regulation, with the proposed regulator backed by royal charter to be written into statute.

Cameron once ridiculed Ukip as a party of "fruitcakes, loonies and closet racists".

Sun associate editor Trevor Kavanagh, formerly the paper's political editor, compared Ukip favourably to the Tory Lib-Dem coalition in an article headlined "Ukip are not so odd as the Odd Couple".

Murdoch's well-known antagonism to the EU is Ukip's defining sentiment, though the tycoon's pragmatism has also led him to back the Scottish National Party and Ireland's Fine Gael in different editions of the paper

However, commentators urged Farage to exercise caution in his response to Murdoch's apparent enthusiasm.

"Farage must realise that there is another maverick contender for Murdoch's hand: Boris Johnson," said media pundit Roy Greenslade, himself a former Sun editor.

"If Johnson were leader, the Sun's master would surely get right behind him. Then again, perhaps Farage would do the same."