Sterling rises vs weaker dollar, boosted by poll

* Sterling up 0.5 pct vs dollar at $1.5130; steady vs euro

* Opinion poll shows big Conservative lead, lifts pound

* BoE's Dale: QE feeding through, may do more if needed

By Jessica Mortimer

LONDON, March 12 (Reuters) - Sterling rose against the dollar on Friday, lifted by broad weakness in the U.S. currency and by an opinion poll showing the opposition Conservatives on course to win a majority in an upcoming general election.

The pound's movements were driven mainly by the dollar, which fell on reports U.S. President Barack Obama plans to nominate San Francisco Federal Reserve Bank President Janet Yellen, seen by many as dovish, as central bank vice chairman. [ID:nN11257901]

It also gained support early in the session by an online opinion poll by Angus Reid Public Opinion showing the Conservatives well ahead of the ruling Labour Party, contrasting with other surveys showing the race too close to call. [ID:nLDE62B0IS]

Investors remained cautious, however, as most recent polls have suggested the election -- expected in May -- could result in a hung parliament, potentially hampering any incoming government's efforts to cut the UK's ballooning budget deficit.

Analysts also pointed to the fact that Angus Reid polls often show lower support for Labour than other surveys, while another daily survey by YouGov in the Sun newspaper put the Conservatives only three points ahead of Labour.

"The pound did go up on the opinion poll," said Gavin Friend, currency strategist at nabCapital, but added most of today's moves in sterling "have been all about the dollar".

"Most of the bad news has been priced in to sterling now -- on the election and the economy -- and it will need something new to give it a push lower," he said.

At 1600 GMT, sterling was up 0.8 percent against the dollar GBP=D4 at $1.5174, off an earlier high of $1.5174.

The euro was down 0.2 percent against the pound EURGBP=D4 at 90.62 pence, while sterling's trade-weighted index =GBP rose 0.5 percent to 77.2.

"The November and December 2009 highs at 91.50 pence are the key barriers to further euro upside here. Last week's rally stalled at this level and remains the key barrier to further sterling losses," CMC Markets analyst Michael Hewson said in a note to clients.

The pound shrugged off comments from Bank of England policymaker Spencer Dale.

Although Dale said the central bank was still ready to provide more stimulus if needed, he added that much of the impact of the Bank of England's asset purchase programme has yet to feed through to the economy. See [ID:nLAH006716]

"The Dale comments have a dovish tone, but sterling has not really reacted and thus far looks to have been driven by external factors (weakness in the dollar), as can be seen by the relative stability of the pound against the euro," said Jeremy Stretch, currency strategist at Rabobank.

Earlier this week, sterling skidded to one-week lows against the dollar and euro after data showing below-forecast manufacturing output and a sharp fall in UK exports.

Sterling has fallen more than 6 percent on a trade-weighted basis from its January highs.

Data releases in the UK are sparse ahead of BoE minutes and employment data due next Wednesday.