Oil holds gains after settlement as poll suggests no Brexit

* Oil prices up but well off session highs

* Sterling reaches 2016 high against the dollar

* Bulk of Brexit referendum results expected 0100-0300 GMT (New (KOSDAQ: 160550.KQ - news) throughout, updates prices and market activity)

By Devika Krishna Kumar

NEW YORK, June 23 (Reuters) - Oil prices held gains in post-settlement trading on Thursday, with Brent crude rising above $51 a barrel after a YouGov (LSE: YOU.L - news) poll showed the "remain" camp ahead in Britain's referendum on European Union membership.

Crude prices had settled 2 percent higher after a volatile session, with investors less worried about prospects for the global economy on the growing view that Britain would remain in the EU.

A poll by YouGov for Sky News showed respondents had voted 52 percent to 48 percent to remain in the 28-country bloc, after voting ended at 2100 GMT.

After the poll, sterling rose around 0.75 percent against the U.S (Other OTC: UBGXF - news) . dollar to $1.4998, its highest since Dec (Shanghai: 600875.SS - news) . 17.

Brent crude settled up $1.03, or 2.1 percent, at $50.91 a barrel. U.S. crude settled at $50.11 a barrel, up 98 cents. Both contracts shot up in the last few minutes of trading. Brent crude rose to a high of $51.12 a barrel after the YouGov poll.

"I think one of the biggest implications is that uncertainty is resolved. People have been antsy and nervous and that always causes investors to be anxious and not be in the markets as much," said Tom Barkley, a British citizen and professor of finance practice at the Whitman School of Management of Syracuse University in New York.

Commodities and other financial markets had been on tenterhooks ahead of Britain's referendum on EU membership.

While the upside potential is tempered, the possible downward drop in markets is not likely to be symmetric, Barkley said.

"If results are counted and Britain leaves, it would be a big negative shock for all markets - stocks, commodities and currencies ... because the market had factored in a 'remain'."

The dollar index was down 0.4 percent. While the sterling's rally to 2016 highs weighed on the dollar, lower U.S. jobless claims limited the greenback's drop as the data bolstered the outlook for the American economy and chances for a rate hike. A weaker dollar makes greenback-denominated oil less expensive for users of other currencies.

Oil prices drew some support early in the session when market intelligence firm Genscape's report of a drawdown of nearly 1 million barrels at the Cushing, Oklahoma storage base for U.S. crude futures during the week to June 21, traders who saw the data said. (Additional reporting by Barani Krishnan in NEW YORK and Karolin Schaps in LONDON; Editing by David Gregorio and Chris Reese)