By Jemima Kelly

GLASTONBURY, England (Reuters) - Mud-covered revelers at Britain's Glastonbury festival were in high spirits as the second day of music got under way on Saturday, with British star Adele's performance keenly awaited though many were still mourning Britain's vote to leave the European Union.

The music and performing arts festival, held at the Worthy dairy farm in Somerset, southwestern England, is known for its wet weather and "wellie"-wearing fans, who trudge through the farm's muddy fields in rubber boots and hope desperately to return to find tents still dry, and where they left them.

This year's event has proved to be no exception. Though sunshine did sometimes pierce the clouds, rain poured down for long periods on Friday and Saturday, and more showers were expected on Sunday.

International superstar Adele, 28, known for her chart-topping hits on heartbreak such as "Someone like you" and "Rolling in the Deep", forms part of an all-British line-up of headliners at this year's festival.

Rock band Muse took the final slot on the main Pyramid stage on Friday night, putting on a visual spectacle for a crowd of almost 75,000. Fellow British rockers Coldplay top the bill on Sunday.

Adele, who collected four Brit awards earlier this year, and last month was named songwriter of the year at Britain's Ivor Novello awards, last performed at Glastonbury in 2007, but not on the main stage.

"I am so excited. I think there's set to be some teary moments because she's just special, isn't she?" said 24-year-old fan Helena. "I feel like it's going to be a powerful performance."


Many of the young revelers said they were still upset over Britain's referendum decision to leave the EU, revealed in the early hours of Friday morning when most at the festival were still asleep. Surveys indicated that the vast majority of young voters had been in favor of staying in the EU.

Some performers, including Damon Albarn and Foals frontman Yannis Philippakis, shared their sadness from the stage.

"My heart is broken," Albarn told the crowd gathered at the Pyramid Stage to watch him play alongside the Orchestra of Syrian Musicians, a group of musicians who fled the Syrian civil war whom he has brought together from around the world. "Democracy has failed us."

There had been worries that not enough of the more than 150,000 festival-goers would vote, and that this would affect the outcome; no polling stations were allowed on site, so those arriving before Thursday had to either submit postal votes or appoint proxies.

But a survey of more than 1,000 Glastonbury attendees, commissioned by the Times newspaper, found that 78 percent had cast a ballot - higher than the 72 percent nationwide turnout. It found 83 percent had voted "Remain".

"I think we're just going to move abroad and never come back to England," said 23-year-old Ed.

Jeremy Corbyn, the leader of the opposition Labour party who had campaigned for Britain to stay in the EU, had been scheduled to talk at the festival on Sunday, but pulled out.

This year's Glastonbury saw various tributes to the late British rock star David Bowie. U.S. composer Philip Glass's "Heroes" symphony, based on Bowie's album of the same name and written 20 years ago, was to be performed just before midnight on Saturday, accompanied by a laser show.

Glastonbury runs until June 26, with James Blake, Tame Impala and Earth, Wind and Fire all due to perform.

(Reporting by Jemima Kelly,; Francis MacGuire and Sarah Mills; Editing by Kevin Liffey)