The BBC has become embroiled in an alleged £10,000 betting scandal involving the winner of the Great British Bake Off.

Ladbrokes have accused BBC employees of placing a string of large bets on the winner of the show ahead of tomorrow night's final - and encouraging their friends and family to do the same.

The bookmakers launched an investigation amid fears staff at the corporation and those linked with the programme's production company may be trying to cash in on their inside knowledge.

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Bookmakers Ladbrokes has suspended betting on the final of the Great British Bake Off amid fears BBC staff and those linked with the production company behind the series may be trying to cash in. Pictured: Two of the three finalists who go head-to-head in tomorrow's final of the baking show, Ian Cumming and Nadiya Hussain

It is feared staff may have placed large bets on the winner of the BBC One show, with prior knowledge of who is crowned the best baker thanks to the final being recorded in advance. Pictured: Finalist Tamal Ray, 29

The Sun reported that 42 new gambling accounts had been opened with Ladbrokes which were linked to either BBC workers – including a suspected executive - or employees at production company, Love Productions.

It is now claimed that the flurry of unusual betting activity - which apparently involves 529 bets from the suspicious accounts - could cost the bookies £10,000.

The show, starring Mary Berry and Paul Hollywood as judges, is pre-recorded - and the winner is already known to a small group of insiders.

But viewers will not know who is crowned champion until the final airs tomorrow night. Those in the running are Ian Cumming, 41, Nadiya Hussain, 30, and Tamal Ray, 29.

A source from Ladbrokes told The Sun: 'Whoever's doing this thinks they're being very clever. But they aren't that smart as they've been using their own names to open accounts.

'Pretty much all the accounts punted on one baker. They clearly know something we don't.'

The bookmakers were originally forced to suspend betting on this year's winner in week one of the show after 90 per cent of bets were placed on one contestant.

That baker's odds had started at 12/1 but quickly reduced to 6/1, then 3/1 and then evens.

The wagers were placed in the days leading up to the show, with betting suspended on the day the series launched.

It is thought an investigation may now be launched into the flurry of unusual betting activity over Bake Off. Pictured: Show judges Mary Berry and Paul Hollywood with presenters Mel and Sue

At the time, many of the wagers were placed in shops around Ipswich, although the contestant was not known to have any links to the Suffolk town.

The bookies said several customers asked to place the highest amount possible on one contestant which raised suspicion.

A spokesman for the bookmaker said at the time: 'When you see a run of bets like this for one contestant at the expense of everyone else, that can be a sign to suspend betting for a bit to assess the situation, and that's exactly what we did.'

Pretty much all the accounts punted on one baker. They clearly know something we don't Ladbrokes source

When betting reopened, Tamal, Nadiya and Ian were favourites, all with odds of 3/1. The market has since been suspended and reopened numerous times since then, a spokesman said.

Ladbrokes said it has not notified police over its suspicions - which mainly centre around this activity at the start of the series - but said it was unsure whether it would continue to take bets on next year's show.

It is illegal to place a bet if you already know the outcome.

Meanwhile, William Hill, which is believed to be the only bookmakers still accepting bets on the show, said they felt 'comfortable' that the BBC had kept the result 'quiet enough'.

Betting for tomorrow's final opened up at 9am yesterday and the bookmaker said activity was 'sensible' at the moment.

'There is always a risk for us because some people obviously know the outcome of things in advance - it's the same risk we take with the likes of Eastenders and the royal baby,' he told MailOnline.

'But we are comfortable with the market as it stands - although we will have one compiler keeping an eye on it all day, which we wouldn't usually, to ensure that remains the case.

'At the moment, betting is pretty much even for all three contestants.'

A similar incident happened two years ago when bookmakers Coral was fearful an insider had leaked the name of the eventual winner of the 2013 series, Frances Quinn.

It suspended betting after 90 per cent of wagers favoured Miss Quinn when the odds quickly fell to 11/10.

The children's clothing designer had been seen as an outsider to take the top prize, as judges Mary Berry and Paul Hollywood regularly criticised her spectacular creations as a victory for 'style over substance'.

This year's show, which is the eighth series of Bake Off, will come to an end tomorrow night.

Ms Hussain, a 30-year-old mother-of-three from Leeds, is favourite to win the contest and will go up against travel photographer Mr Cumming and trainee anaesthetist Mr Ray.

A spokesman for Ladbrokes told MailOnline: 'We flagged at the start of the series that we thought something smelled a bit strange. We are looking into it further.

'If we feel we've had the equivalent of a custard pie thrown in our faces we will think twice about whether we should bet on markets like this again in the future.'

They added: 'Our investigation will focus primarily on the activity at the start of the series. At this stage, it remains an internal investigation so we can't comment further.'

A BBC spokesman said: 'We have no knowledge of these claims and have asked The Sun to provide us with details to be able to look into it. We are still waiting.

Love Productions said: 'We take any allegation of breach extremely seriously.'