Britain's biggest bookmakers can't decide whether Leicester City will win the league again or get relegated

Britain's biggest betting companies are far more optimistic about Leicester City FC's chances next season than they were last year, following the club's shock Premier League win that cost bookmakers millions.

But there are signs they also suspect that success was a one-off.

Bookmakers gave Leicester City odds of 5000/1 at the beginning of the 2015/16 season, meaning anyone who bet £20 on the club winning the league collected a £100,000 return on Sunday.

Now Ladbrokes has slashed the team's odds of retaining the title from 33/1 to 25/1 as a flurry of customers have bet on the club doing it twice in a row.

However it has also placed 20/1 odds on Leicester being relegated, suggesting that many think the team's success was a fluke.

Meanwhile a Champions League seems within the realm of possibility, with odds of 80/1 - still far lower than their previous Premier League odds.

Rival William Hill is even more bullish, with odds of 66/1 for a Champions League win - down from 100/1 since their title win. Like Ladbrokes, William Hill pegs a Premier League win at 25/1, but it also thinks relegation is even more possible at 16/1.

Paddy Power is less concerned by a Leicester City Premiership repeat, with odds currently at 33/1, and odds of 14/1 for relegation.

Alex Donohue of Ladbrokes told Business Insider that punters didn't want to be surprised again:

"Those who missed the 5000/1 boat are already steaming into Leicester at far shorter odds, confident they can kick on and become a force in English football for years to come. We should whisper it, but we're actually offering shorter odds about them being relegated next season than them retaining their title."

Paddy Power, meanwhile, said Leicester's win had already altered the way people were betting for next season.

"It has completely changed our customers' behaviour in that they're backing the underdogs like never before," a representative said.

"Burnley, who were promoted only last week, have already been backed by over 60 customers. Previously these sides would only have received a handful of bets all season."

Some analysts have suggested the Leicester City title win could be worth as much as £150 million to the club, thanks to increased matchday attendance and TV/commercial revenues.