* Bookmakers forecast record business from soccer World Cup
* Tournament highlights fans' mobile betting and bet variety
* Market share vital; industry changes afoot
* Britain's higher taxes expected to spur consolidation
* Bookies develop apps, websites to keep clients with them
By Keith Weir and Padraic Halpin
LONDON/DUBLIN, May 23 (Reuters) - Tech-savvy gamblers using smartphones and tablets to bet on live match action will help to make next month's soccer World Cup the most lucrative sports event ever for British bookmakers and bring welcome relief from tough market conditions.
Betting companies in Britain are grappling with tighter regulation and an additional tax burden of 400 million pounds ($675 million) over the coming year - moves that have weighed heavily on their share prices.
But the Brazilian sporting drama dovetails with a surge in soccer gambling - now rivalling horse racing as the main online revenue earner for British and Irish bookies - and could mean industry earnings double from the last World Cup.
"We are anticipating that we will turn over well over 200 million (pounds) this tournament. In 2010 it was circa 100 million," said Terry Pattinson, trading director at William Hill, Britain's largest bookmaker.
The big bookmakers expect to take more money online than in their betting shops as younger gamblers, raised on a steady stream of live TV action, reach for mobile phones to place bets.
Furthermore, they expect returns to be boosted by two new aspects of customer behaviour: more bets will be placed by fans from their sofa or neighbourhood pub - rather than by seasoned gamblers calculating the odds - and punters can now make multiple bets on a staggering number of options as the games unfold.
"Most of the popular bet types are around players, whether they score goals, get yellow or red cards. How many corners in a match. It's about action," said Pattinson, who oversees the odds offered by the bookmaker from his base in the northern English city of Leeds.
Ladbrokes plans to offer more than 250 markets on each game covering all aspects of play.
Bookmakers have already begun to bombard television viewers with advertising - many of them starting weeks before the World Cup's June 12 kickoff.
"It will be an enormous, one in four year opportunity, to attract mass market customers," said Patrick Kennedy, chief executive of Irish bookmaker Paddy Power which is forecasting a doubling of World Cup turnover to 160 million euros ($220 million).
But behind the usual scramble for market share this time lies a battle for survival.
In December the British government closes a loophole that has allowed bookmakers to minimise tax bills on online earnings by basing operations offshore in places like Gibraltar. Then in March 2015 it will raise taxes on the high stakes gambling machines that account for a big slice of betting shop revenues.
Faced with extra millions on their tax bills, the big brands will have to cut costs to survive - sparking a wave of industry consolidation that will squeeze out anyone who does not have a big customer base.
"A good World Cup will have more of a defining impact on the position of the player in the market," said Simon Oaten of business consultancy Deloitte. "The larger operators have an increasing advantage in the sports betting sector."
In an attempt to keep punters' attention after they have made that first World Cup bet, bookmakers are developing sophisticated websites and apps to keep pace with live TV.
Paddy Power became the first bookmaker to have an app in the Apple Store before the last World Cup in 2010 when mobile betting was in its infancy and now generates an industry-leading 54 percent of online revenue via smartphones and tablets.
The Dublin-based group also uses live match pages and guest bloggers including former England midfielder Paul Scholes to rival minute-by-minute commentary on soccer websites.
Other bookmakers keep their customers engaged via accumulator bets - where a gambler bets on a series of linked outcomes - which are becoming increasingly common.
"The most popular bet will be an eight-fold accumulator on all eight favourites to win their respective groups," said William Hill's Pattinson. "If that goes true to form we might be in for a tough opening," he added.
One of the usual boosts to English bookies' takings - a patriotic surge of betting on the national team - is likely to be absent this time, however. The English World Cup 2014 team me consists largely of untested young players and as a result is ranked 28-1 to win.
Hosts Brazil, trying to win the World Cup for a record sixth time, are 3-1 favourites.
Pattinson hopes nonetheless that the English team gives fans a decent run for their money before it has to leave.
"If they get through to the final stage and maybe go out on penalties, that will suit me fine," he joked. ($1 = 0.5935 British Pounds) ($1 = 0.7302 Euros) (Writing by Keith Weir; additional reporting by Sam Cage in Dublin; Editing by Sophie Walker)