The Jamie Spencer-ridden colt led throughout the two-mile contest. Turning for home, the son of Duke Of Marmalade was still travelling well for Spencer despite horses lining up in behind ready to challenge the gelding.
However, the five-year-old was not for passing and fended off the challenge of second-placed Pallasator and third-home Sheikhzayedroad.
A delighted Bell said: "Big Orange is a very brave horse. He gives his all. He has got as very good mind and engine and he has good limbs as well - that combination is a potent force.
"Big Orange is an enormous horse and big horses tend to mature with age. It is a bit of cliché but like a fine wine he is getting better with age. He is just a star and we are so lucky to have him. He has a massive stride and such a high cruising speed. Touch wood he is very clean limbed and loves this fast ground.
"I thought he was headed and said to Claire 'he is beat' but Jamie always knew he was going to win. We saw Big Orange at a breaking yard in the summer of his two-year-old career. Bill wasn't going to send him in but this horse cantered by and we said 'God, this horse moves well let's give it a go' and the rest is history.
"He was a very raw product as yearling and was a box-walker so he didn't go to the sales as he would have made a ham sandwich. It's great because he has now won a lot of prize money with still more to come. He won well today and won the Princess of Wales's Stakes at Newmarket by two lengths this year. Last year he won those races by a neck and half a length so you would have to say he has improved and I think the handicapper would probably say he has as well.
"In the Princess of Wales's Stakes he beat the Grey Gatsby who is a Group One winner so our horse is a high-class horse over both a mile and a half and two miles and he likes fast ground so he travels very well."
As for the future, Bell suggested another trip to the Melbourne Cup, in which he finished a two and a half-length fifth last year was a possibility: "Bill [Gredley, co-owner] is not so keen [on Melbourne Cup] but Tim (Gredley) is very keen and I am quite keen, although I think we need to see what weight he gets before we commit. There are other possible targets like the Canadian International or Hong Kong. There is a lot to be chewed over and Bill usually opens a good bottle of wine when we talk plans!
"The Melbourne Cup is a handicap so there is no point flying round the world if you think you've got too much weight. I've got to talk to Bill but I think we will make the entry. The Caulfield Cup is also a handicap so that is an option but we would have to see what he is rated. I doubt his rating will go up today but we will have to see what weight he is given before deciding about Melbourne. He has got the attitude to do it and I enjoy the Melbourne experience more than any other experience I have had on a racecourse so we might go back if we feel we could troubling the judge."