A reality TV betting scam that made a gang £105,000 has been foiled by a team of investigators.
Betfair became suspicious over bets on shows like X Factor
Online betting firm Betfair became suspicious after a five-man ring won bets placed at the last minute on shows like ITV's X Factor.
The firm's "integrity team" have suspended the accounts, frozen £45,000 of the gains and called in the police.
BT said it was "urgently investigating" the possibility that one of its employees was tipping people off.
Although Betfair has managed to freeze some of the winnings, £60,000 had already been withdrawn.
The gang made £30,000 by betting on X Factor alone.
Other shows involved included Big Brother, Strictly Come Dancing, I'm a Celebrity... Get Me Out Of Here! and Hell's Kitchen.
A spokesman for Betfair said: "We take very seriously the integrity of betting on our markets and have no hesitation contacting police when people may be betting fraudulently.
"The problem is that it's not certain what law has been broken but we have spoken to police and they are looking into it."
X Factor judge Simon Cowell said the fact the ring had been caught meant that punters were "safe to put a bet on now".
"Maybe in a strange way it's good that it's been caught now so at least people who put bets on these shows know that there's people looking into this stuff.
"With anything like this, there's always the risk of insider knowledge but they've got caught."
But he said he was surprised by the scam because producers of the X Factor often did not know the results of phone votes until the last minute.
"I can tell you for sure that last week, as we were walking on the stage to hear the results, I know the producers were saying to each other, 'we still don't know who's actually going home' because it was changing at the last second."
Telephone lines for the reality shows involved are supplied by BT but operated by service provider Harvest Media.
"We are urgently investigating this," a BT spokesman said.
The gang, which made wagers from computers in the London area, are believed to have started their scam at last year's BBC Sports Personality of the Year awards.
Members of the ring are thought to be in their early 30s and well-educated.
The group began by placing small bets but those amounts grew as they kept winning.
They also tried to hide their tracks by intentionally losing small amounts of money on other bets.