* Cameron in new pitch for votes before 2015 election
* Promises tax cuts, easier mortgages to help with livingcosts
* Says UK may be forced to ditch European rights accord
* Ridicules rival's tax and policy plans as "nuts"
By Guy Faulconbridge and Andrew Osborn
MANCHESTER, England, Sept 29 (Reuters) - British PrimeMinister David Cameron began setting out his stall for the 2015election on Sunday by talking up a contested plan to boost homeownership and suggesting Britain may ditch Europe's main humanrights treaty, an object of hatred for Eurosceptics.
Seeking to reverse days of gloomy opinion polls before thestart of his ruling Conservative party's annual conference,Cameron said his decision to bring forward the government's new12-billion-pound mortgage guarantee scheme would be a shot inthe arm for would-be home owners.
Rejecting criticism from political rivals and economists whosay it risks stoking a housing bubble, Cameron made clear heplans to place the economy at the heart of the next election ata time when data suggests it is growing.
"The housing market is recovering, but from a low base,"Cameron told BBC TV in an interview, saying that RBS,NatWest, and Halifax, all part-owned by the state, would takepart in the new scheme, due to start next week, three monthsearly.
"Talk of a housing bubble to people here in Manchester orSalford and they would literally laugh in your face," he added,arguing that the house price inflation seen in London and thesoutheast of England was not representative of the rest ofBritain.
Cameron's decision to bring the scheme forward by threemonths appeared rushed, with crucial details unavailable on theeve of its launch.
Trailing the Labour party by 11 points in the latest pollafter Labour received a boost from its own conference, Cameronis trying to convince his party as well as voters that he canwin outright in 2015 and govern alone, rather than in atwo-party coalition, as is now the case.
ELECTION "WIDE OPEN"
He said on Sunday that the outcome of the next election was"wide open", but that he had to win back centre-right voters whohad drifted towards the UK Independence Party (UKIP), and toshow voters he was helping them with rising living costs.
"We have a huge battle," he said.
Labour has accused Cameron of delivering a slow economicrecovery for the rich at the expense of the poor.
Real wages have fallen since Cameron took power in 2010while inflation has pushed prices for everything from utilitybills to transport fares higher, even as economic indicatorshave begun to pick up across the board.
Cameron said he had had to contend with a huge hole in thepublic finances left behind by Labour, which was in power from1997 to 2010, while suggesting he would try to cut or freezetaxes, and look at "all markets" to ensure they were treatingconsumers fairly.
"We have to make the big argument about living standards,which is (that) the only way to sustainably raise livingstandards is to keep the recovery going," he said.
"To keep on creating jobs, and we are creating those jobs;to keep on cutting the deficit, because that keeps interestrates and crucially mortgage rates low; and to keep on cuttingpeople's taxes, because that is the way to give people more oftheir own money in their own pockets."
Cameron refused to match a promise by Labour leader EdMiliband to freeze energy bills, however, ridiculing it and whathe said were ill-considered Labour plans to raise taxes on bigcompanies in a range of sectors.
"If you take his approach as a whole, it is anti-business,it is anti-enterprise, it is saying to companies that areinvesting in Britain: 'I am going to put up your taxes'," saidCameron. "It is nuts, frankly, to put up corporation tax."
Cameron also moved to try to neutralise what it emerging asone of the biggest threats to his re-election: UKIP.
With no lawmakers in the British parliament, UKIP, whichwants Britain to leave the EU and an end to what it calls"open-door immigration", has seen its support surge in opinionpolls.
Surveys suggest it has begun to siphon off support from theConservatives, notably in decisive "swing" constituencies thatwill help decide the 2015 election.
Under pressure from UKIP and like-minded lawmakers in hisown party, Cameron has promised to try to renegotiate Britain'sEU ties and hold a referendum on its continued membership by theend of 2017 if he is re-elected.
On Sunday he went further, saying Britain might be forced toabolish the Human Rights Act, which since 2000 has made theEuropean Convention on Human Rights, signed by the 47 members ofthe Council of Europe, enforceable in Britain's courts.
A series of high-profile cases, such as that of radicalcleric Abu Qatada, who resisted British attempts to send him toJordan to face terrorism charges for more than a decade, haveangered many voters and exposed successive governments to theaccusation that they do not control Britain's own borders.
In July, the European Court of Human Rights, which upholdsthe convention, angered British critics further, ruling thatBritain had violated the rights of three murderers by jailingthem for life with no prospect of release.
Asked if Britain should leave the Convention, of which it isa founding signatory, Cameron said: "It may be that that iswhere we end up."
- Politics & Government