Punter Paul Dean proved to have made a wise decision on Thursday when he opted for a partial cash out of £250,000 on his remarkable £5 accumulator.

Dean stood to bank £511,225 if he allowed the bet to roll on and Envoi Allen won the opening Marsh Novices’ Chase on day three of the Cheltenham Festival.

However, he instead took Betfair’s cash-out offer after overnight deliberation — although he still stood to land another £50,000 if the previously-unbeaten Envoi Allen took his perfect record to 12 from 12.

Sent off the 4-9 favourite under Jack Kennedy, the race was going along as expected until he appeared to take off a stride too early at the fourth fence, brushing through the top of it and crumpling on landing.

Dean tweeted immediately after the race that he hoped Envoi Allen was OK following his fall, and that appeared to be the case, although jockey Jack Kennedy was a disconsolate figure as he walked back up the track to the weighing room.

Speaking earlier in the day, Dean said: “It’s a fantastic offer and I couldn’t be happier. I’ve definitely done the right thing.

“It’s all about Cheltenham for me and I love having small ante-post bets and the dream of a big win over the winter. I usually start placing my bets at the next best race meeting after Cheltenham — that’s Royal Ascot in June.”

The accumulator kicked off with Golden Horde (12-1) and Hello Youmzain (10-1) winning the Commonwealth Cup and Diamond Jubilee Stakes respectively at Royal Ascot, before Shishkin, who he had backed at 4-1, claimed the Arkle and Bob Olinger, who he had at 25-1, lifted the Ballymore.

Dean said: “This year I really fancied Golden Horde and Hello Youmzain at Royal Ascot. Shishkin was an obvious one, while Bob Olinger looked so good in his bumper.

“I also love his trainer, Henry de Bromhead, and Bob Olinger’s sire, Sholokhov, plus the Ballymore is my favourite race in the world. I’ve backed all the big winners of the race over the years.

“I just love Envoi Allen and want to be able to cheer him home today, that’s why I have partially cashed out. Come on Envoi.”

Asked what he would do with the money, Dean said: “I’ll be going on a lot of holidays!

“It’s my mum and dads 70th this year, so we’ll be going to New York and to some of the best golf courses in the world. I really want to play Bethpage and Sawgrass. And I think I’ll buy a horse.”