(This article accompanies a Wider Image photo gallery available on http://reut.rs/1x2X4Wc)
By Conor Humphries
BELFAST, Sept 2 (Reuters) - In Northern Ireland, the flags of Israel and the Palestinians are potent symbols of conflict - but here they divide Catholics and Protestants rather than Jews and Muslims.
In the complex web of alliances that underpins the British province's flag-obsessed politics, the Star of David has been adopted by pro-British Loyalists, mainly Protestants, many of whom sympathise with Israel.
Flying the green, black, red and white flag of the Palestinian territories, meanwhile, is a sign of support for Catholic Irish Republicans and their aspiration for a united Ireland against what they see as British occupation.
The flags are among dozens that have been adopted by the working class Catholic and Protestant areas that have for decades been at the focus of sectarian violence in Northern Ireland to fly alongside the ubiquitous British and Irish flags.
"I've been in plenty of conflict zones, but I have never seen such an intense use of flags to mark territories," said Peter Shirlow, a professor of conflict resolution at Queen's University Belfast.
"This display of loyalty and faith is embedded in the culture ... It's a century-old tradition."
The official state flag, the Union Jack, is itself divisive, signifying not just loyalty to the British crown, but for some Republicans, hostility to Irish Catholics.
The flag issue is so potent that raising or taking one down has been enough to spark riots or protests, as happened in December 2012 when Belfast city council decided to restrict the flying of the Union Jack above city hall.
Almost two years later, a hard core of a half-dozen protesters still gather every week at city hall.
Some moderate Belfast residents scoff at their anger over how many days a year the flag now flies, dubbing them "fleggers," a jibe at the pronunciation of the word flag with a strong Belfast accent.
"The middle classes like to sneer at the young people who are engaged in this protest," said Brian Watson, 62, who works with young people in the city's loyalist heartland, the Shankill Road, which for much of the year is criss-crossed with blue, white and red bunting and flags on every lamppost.
"(But) they come from deprived areas and the flag issue has become a focus for their anger and frustration over jobs and social justice," he added.
Equally potent for Loyalists is the green, white and orange tricolour of the Irish Republic, which for many has associations with militant Irish nationalism and the three-decade fight against British rule - the "Troubles" - in which over 3,000 people died.
A depiction of the 'plough in the stars' constellation on a blue background, the flag adopted by the left-wing Irish Citizens Army a century ago, is associated with the Irish National Liberation Army, which disarmed in 2010.
In addition to the Israeli flag, particularly visible in recent weeks during the conflict in Gaza, Loyalists fly the flags of the other countries of the United Kingdom: Scotland, Wales and England.
Flags of British army regiments the Special Air Service (SAS) and the Parachute Regiment are flown in a nod to their role countering Irish militants during the Troubles.
Loyalists, who march in July every year to celebrate a military victory by Dutch-born Protestant King William of Orange in 1690 that cemented Protestant domination in the province, often fly Orange Dutch football flags.
Occasionally Republicans fly the stars and stripes because Irish Americans were among their most loyal supporters during the Troubles.
But they also fly the flag of Washington's enemy Cuba, with left-leaning nationalist groups paying tribute to revolutionary heroes Che Guevara and Fidel Castro.
Confused? Who wouldn't be?
"Imagine being a tourist wandering through Belfast wondering what's going on," mused comedian Jake O'Kane during a sketch on a BBC current-affairs show last year.
It was all too much for one Belfast shop-owner this Summer who had mounted a World Cup window display featuring the orange, white and green flag of Ivory Coast.
He posted a large notice under the flag saying simply: "This is Ivory coast, NOT Republic of Ireland."
(Additional reporting by Maurice Neil; editing by Stephen Addison)