Britain's FTSE supported by AB Foods as U.S. election looms

* FTSE 100 up 0.5 pct at close

* Primark owner beats expectations

* Marks and Spencer to close stores

* Imperial Brands (LSE: IMB.L - news) drops after results (Adds detail and quote, updates prices at close)

By Kit Rees and Alistair Smout

LONDON, Nov 8 (Reuters) - Britain's top share index rose slightly on Tuesday in choppy trade as voting in the U.S. election got underway, with better-than expected-results from Primark-owner AB Foods helping to support shares.

AB Foods jumped 5.8 percent after the group said it expected to benefit from Britain's vote to leave the European Union (KSE: 000910.KS - news) and saw profits rising despite a weaker pound hurting margins at its British stores.

The company's results beat analysts' average forecasts. It said next year's results would be helped by its sugar business, and a weak pound would improve the value of its overseas earnings.

"Helpful FX moves are helping sugar margins (already up on better global sugar prices), bringing focus back to the 'ingredients/agriculture' segment to prove that the ABF story can still be something other than discount fashion and Primark," said Mike van Dulken, the head of research at Accendo Markets.

The stock was the stand-out mover on the FTSE 100, which ended a choppy session 0.5 percent higher at 6,843.13 points.

The index rose 1.7 percent on Monday, its biggest daily rise since early September, to end a 5 session losing streak.

Signs that Republican Donald Trump was gaining in the polls last week knocked appetite for equities globally. However, the FBI declined to bring charges against his rival, Democrat Hillary Clinton, over the weekend, and several polls out on Monday gave her a lead.

Markets have been spooked by the prospect of a Trump presidency, given his uncertain policy stance, and have generally been positioned for a Clinton win, which analysts say represents the status quo and could spark a relief rally.

"We believe that a Clinton win would see a rally in European stocks. A Trump win, on the other hand, could bring forth a correction," analysts at Barclays (LSE: BARC.L - news) said in a note. The result will likely be known before European markets open on Wednesday.

Top faller was Marks & Spencer (Frankfurt: 534418 - news) which dropped more than 5 percent after it said it was closing stores as profits and clothing sales fell.

"Given our bearish view on UK consumer confidence and future clothing spend we hope that M&S' five-year recovery strategy will be a case of "two steps forward, one step back" but fear it may be "one step forward, two steps back"," analysts at Jefferies said in a note.

Imperial Brands also fell after its own results. While it beat full-year expectations, that failed to assuage concern over new investment. (Reporting by Kit Rees; Editing by Tom Heneghan)