UPDATE 2-Cameron backs referendum on new Britain-EU deal

* Cameron has promised to renegotiate terms with EU

* Conservative eurosceptics want to reclaim powers from EU

* No time frame or indication of what question would beasked

(adds quotes and background) By Guy Faulconbridge and Mohammed Abbas

BIRMINGHAM, England, Oct 9 (Reuters) - A referendum onBritain's ties with the European Union would be the best way ofagreeing a fresh settlement with the 27-member bloc, PrimeMinister David Cameron said on Tuesday, as pressure mountswithin his party for a vote.

The Conservative Party's restive "eurosceptic" right wing isclamouring to claw back powers from Brussels. Some want a simplevote on staying in the EU or leaving, fearing that the partycould lose votes to the anti-Europe UK Independence Party at the2015 election.

Cameron says Britain should remain in the EU, Britain'sbiggest trading partner, but renegotiate terms as the 17 membersof the EU's currency union redefine their own ties to tackletheir sovereign debt crisis.

Speaking to the BBC, Cameron gave no time frame for a voteor any indication of what could be asked at a referendum. Theprime minister has said he is against an "in/out" plebiscite.

"When we achieve that fresh settlement, it needs consent,either at a referendum or a general election," Cameron said onthe sidelines of the Conservative Party conference in theEnglish city of Birmingham.

"Frankly, a referendum is obviously the cleanest, neatestand most sensible way of doing that."

Europe has divided the centre-right Conservatives fordecades and helped to ng down the party's last two primeministers, Margaret Thatcher and John Major.

Cameron has promised a referendum after 2015 on any futureEU treaty, and has pledged to avoid getting entangled in costlysolutions to the euro zone debt crisis and to try to repatriatesome powers from Brussels.

But some Conservatives want Britain to renegotiate itsrelationship with Europe now, disappointed by Cameron's U-turnon a pre-election pledge for a vote on the Lisbon Treaty.

"Europe is changing - the euro zone is going to integrate.... it is necessary if they are going to save the singlecurrency, but I think that does open up the opportunity forBritain to get a fresh and a better settlement with Europe,"Cameron said.

"I am committed to making sure we do everything to set thatout in the run-up to the next election, to get that freshsettlement and then seek fresh consent for that settlement."

On Sunday, Cameron threatened to scupper EU budget talksunless other members of the bloc agreed to "proper control" ofspending, without specifying what arrangement Britain wouldaccept.

He also lent his support to a proposal for two EU budgets -one for the euro zone and another for cash-strapped Britain andthe other nations outside the single currency.

The prime minister used Britain's veto in December to blockan EU-wide pact designed to help the euro zone, a move thatdelighted eurosceptics in his party but dismayed his LiberalDemocrat coalition partners and other European leaders.

A deal was eventually agreed without Britain.

(Reporting by Mohammed Abbas and Guy Faulconbridge; Editing byKevin Liffey)