How do you breed a £4.5m horse?

"You need the right stallion, the right mare, he has to match up physically, vet well and then show well" - the essential ingredients to sell a multi-million pound racehorse.

That's according to Hamish McCalmont, whose family have run Norelands Stud in County Kilkenny, Ireland, since 1912.

Their breeding operation hit the headlines with a 4,600,000 (£4.37m) guineas Night of Thunder colt setting a new European record price for a yearling colt in Newmarket.

"It is an amazing result for the whole industry, the team and for Tattersalls, we just hope he goes on to become a champion now," he said.

Book 1 of the Tattersalls October Yearling Sale is Europe's premier yearling sale. When all the big-hitters turn up.

Park Paddocks and Newmarket last week became the focus of the international bloodstock market, welcoming top buyers and sellers from all over the world to do business in the Suffolk town.

Many will stay on this week too for books 2 to 4 (12-16 October), with yearling sales concluding on Friday.

The Night of Thunder colt was just one of a record-equalling 17 yearlings to sell for one million guineas or more. 63 lots sold for more than 500,000 guineas.

"We are all aware of the challenges, particularly on the domestic front in terms of the economy and equally of the unsettled picture globally," said Matthew Prior, managing director at Tattersalls.

"But our business is amazingly resilient. It is a mark of those, who both sell and buy and the passion that they have for horses and racing, that it so far has been able to withstand that uncertainty.

"This is the most important fortnight in the European bloodstock calendar. We certainly got off to a fantastic start," he added.

• A guinea is an old British coin that was officially worth 21 shillings. It equals £1.05 in modern decimal currency
• Horses are bought and sold in guineas at Tattersalls in line with a long-standing horseracing tradition
• The extra 5p in £1.05 traditionally accounted for a 5% commission for the auctioneers
• The guinea stopped being minted in 1814 but the bloodstock industry has kept using it as a nod to its heritage

The record-breaking colt was bred by Mrs Tsui's Sunderland Holdings.

"He's an absolute superstar by a magnificent stallion and out of a mare who has done it as well," smiled Norelands' farm manager Matt Gilsenan.

"He was reared on the farm, and we are thrilled for the team, it's a great boost for them.

"That was above and beyond our wildest dreams."

McCalmont added his heart was pumping with the colt walking around the ring for around ten minutes, as the price kept rising before the sale was made.

"We thought he might make a million, maybe more but you need the right buyers to lock on.

"We wondered a few weeks ago, is this the best colt we have ever had? We had been saying that all year, as he was clearly a very special foal.

"When you get here and see so many beautiful horses being sold in Book 1, you never quite know. You think, is he really the one? Clearly he was!"

Once the bidding passed 2,500,000 guineas, the battle narrowed to M.V. Magnier (Coolmore) and Anthony Stroud (Godolphin).

Magnier took the price from 3,600,000 guineas to 4,000,000 guineas but despite the strong move he could not shake Stroud, who secured the prized yearling.

Purchaser Stroud, a bloodstock agent working on behalf of Sheikh Mohammed's Godolphin operation, admitted the colt was at the top end of their valuation.

"He is from a very good family. He's got the looks, he's got stallion potential and he comes from a very good stud.

"We couldn't be happier," he added.

George Boughey is a racehorse trainer based in Newmarket. He told the BBC he tries to see every horse on the sale ground (477 lots in Book 1), in his bid to find a future champion.

"It is a very important time of the year for us, as we head towards the end of the flat season.

"We are trying to find our horses for next year. We come every year. Tattersalls has been a huge source of our better horses."

Boughey has trained two Classic winners. Cachet, who won the 1000 Guineas in 2022 and Bow Echo in May this year in the 2000 Guineas.

The 34-year-old is the youngest trainer to win both races in the post-war era.

"We are trying to buy a variety of horses, whether it's a speedy horse or a more staying horse (bred and trained to run long-distance races).

"Fundamentally, we are trying to source winners and find good horses.

"It is a buoyant market with some staggering prices and it does make it hard to get them."

Nicolas de Chambure is the fourth generation of his family to take charge of Normandy's Haras d'Etreham - a French breeding company and major player in the worldwide horseracing industry.

His main market is back in France but he decided to bring three of his horses to the UK to sell in Book 1 at Tattersalls.

"We look at the pedigree, the stallion and sometimes the individual that would suit the British market.

"It also spreads our risk by selling horses in different markets.

"There are groups of buyers who go to every sale. But there are people who only go to certain sales.

"Certain horses need a certain clientele, who we can find here more than in France. They are the horses that we bring over and you can be very well rewarded," he added.

"It also helps us to promote our brand taking part in the best sale in Europe."

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