Ladbrokes announced it had stopped taking wagers after a flurry of unusual activity on the BBC cooking show.
The bookmaker noticed suspicious play on one contestant, whose odds started at 12/1 and were reduced to 6/1, 3/1 and then evens.
A spokesman said: “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.”
Many of the bets were placed in shops around Ipswich, although the contestant is not known to have links to the town.
Several of the wagers were the maximum the bookies would take for the show, and 90% were placed on one contestant.
Ladbrokes said several customers came in and asked to place the highest amount possible on one contestant which raised suspicion.
The suspension will not affect bets already placed.
Meanwhile, Penwortham contestant Dorret Conway, 53, survived the first episode of the show on Wednesday night.
The 53-year-old accountant was reduced to tears when her gateau collapsed into a mess on the cake stand.
But professional musician Stuart Henshall was the first contestant to be sent home from the show this year.
The 35-year-old was eliminated from the competition last night after failing to impress judges Paul Hollywood and Mary Berry with his Black Forest gateau, which he made using beetroot.
Mr Henshall said: “In the future I will make Black Forest gateau my way, in the show I covered it in Italian meringue and I put beetroot in it.
“Maybe I should have made it in more a traditional way for Mary. She is awesome and I have followed her recipes for years and Paul’s but hey, I’m not that traditional myself.
“They are both inspirational, and my personal heroes, even if they didn’t like my cake.”
He added: “My worst moment was definitely being the first to go out, after the excitement of getting there. Somebody has to go first and overall it has been a great experience, without a doubt.
“I felt disappointed in myself initially after leaving in the first episode, as I felt I didn’t perform as well as I could. I just hope I don’t disappoint people in my life, but it’s onwards and upwards.”
Mr Henshall got off on the wrong foot by giving his signature Madeira cake a thick caramel glaze, which stuck Hollywood’s teeth together. The judge told him: “The flavours are all wrong, really.”