ON Monday, the issue of concert parties on the shareholder register of Mitchells & Butlers resurfaced, after racing tycoons John Magnier and Derrick Smith issued a statement disclosing the size of their combined shareholding.

Behind the scenes, the long-standing business associates – who have co-owned a string of racehorses – will get the chance to catch up at this autumn’s round of bloodstock auctions.

Their paths haven’t crossed so far – Smith has not joined Magnier at the Goffs auction in Ireland, where Magnier is currently buying racehorses for his Coolmore stud – but both are expected at the Tattersalls October Yearling Sale, which starts next Wednesday.

Plenty to talk about then, as the duo shop for the cream of the unbroken yearlings at the Newmarket horse fair, where last year Magnier bought the most expensive lot, paying 1.2m guineas through his bloodstock agent Demi O’Byrne for a filly called Was.

However, that is small change compared to the $16m Magnier spent on The Green Monkey, a thoroughbred named after one of the golf-courses attached to Magnier’s Sandy Lane resort in Barbados that retired in 2008 without ever winning a race. “Buying unbroken horses is a big gamble,” said The Capitalist’s bloodstock mole. “Because there is no guarantee they will ever win.”

ALSO expected to buy horses at Newmarket next week are Investec’s chief executive Bernard Kantor (right), who is poised to sign a new sports sponsorship deal; property billionaire Sir Robert Ogden; and Qatari royal Prince Fahad al Thani, who has “a new love” of racing after sponsoring the British Champions Series.

The world of billionaire racehorse owners is not without its feuds – “too many egos”, says an insider – but one clash that looks as though it is being resolved is the standoff between Magnier and Dubai’s ruler Sheikh Mohammed Al Maktoum.

The pair have refused to buy yearlings sired by each other’s stallions for years, but earlier this month Magnier’s Coolmore operation bought the Bernardini colt from the sheikh’s Darley stud for $875,000. “It was interesting to see,” noted one observer.

MEANWHILE, an unlikely emerging power in the racing industry is Andrew Tinkler, the chief executive of Eddie Stobart, who has built up a stable of 40 to 50 racehorses since taking an interest in the sport four years ago.

But faced with a choice of horseracing or trucks, Tinkler’s road haulage empire still wins every time – earlier this month, his horse Tell Dad was abandoned at Newmarket as Tinkler rushed off to mix with his 6,500 fans at Stobart Fest.

Not even the news that Tell Dad won £200,000 prize money in the most valuable race of the day could detract from the celebration of trucks, trailers and their drivers. “We all knew where he would rather be,” said an amused mole.

CUBAN cocktails all round at Boisdale of Canary Wharf tonight, as the Cuban ambassador Esther Armenteros is taking a trip to E14 for a private view of Authentic Cuba, an exhibition of photographs by Alejandro Gortazar.

To join Boisdale’s owner Ranald MacDonald for mojitos and Havana Clubs at the Music Fund for Cuba fundraiser, RSVP on 0207 715 5818 or email