And that common cause won't just be on the course. The more affluent Irish racing fans will be helping themselves to their share of the 10,000 bottles of champagne that official race caterers Letheby & Christopher are preparing to serve over the four days. But there are no airs and graces at Cheltenham, even in the expensive seats.

"Nobody quaffs at Cheltenham, they slug, " offers Ryanair chief executive and Gigginstown Stud owner Michael O'Leary, who will be heading to the festival and hopes to have at least one horse running. He remarks on the atmosphere created by "20,000 Irish fellas slugging pints" at Cheltenham.

"It's not like Ascot. The people who go to Cheltenham are going there because they like the racing."

Camaraderie and a shared interest in racing don't prevent a healthy rivalry at Cheltenham, which bookmaker Ciaran O'Tierney says offers a "once in a lifetime chance for the small guy to take on the big wealthy guys". O'Tierney is one of a syndicate of seven people which owns heavily-backed Irish horse Brave Inca, scheduled to run in the Cheltenham Champion Hurdle.

The bookie recounts with satisfaction that Brave Inca pipped O'Leary's War Of Attrition two years ago to win the Supreme Novices Hurdle at Cheltenham. He has high hopes of another coup at this year's festival.

By all accounts, there will be plenty of the "big, wealthy guys" in attendance at Cheltenham. Among those planning to drop in are financier Dermot Desmond, property developers Seamus Ross and Sean Mulryan and, naturally, bloodstock millionaires JP McManus and John Magnier. All have horses running.

Equine aficionados including Michael Smurfit, Tony Ryan and EU internal markets commissioner Charlie McCreevy will doubtless put in appearances. And while September's Ryder Cup will take the laurels as this year's top corporate sponsorship event, some big corporates will be laying it on for Cheltenham. Among those heading for the event is a contingent from Anglo Irish Bank, sponsor of the Supreme Novices Hurdle, which will be showering lavish hospitality on its most favoured British and Irish customers. AIB will also be ferrying British clients to the race meeting for some schmoozing.

For Irish tour operators, Cheltenham is a high note in the annual calendar. Carlow-based tour operator Joe Tully, for example, is handling transport and accommodation bookings for over 2,000 Irish punters heading for Cheltenham.

And among those slugging the champagne and other tipples will be a large number of well-heeled Irish business people who have been busily booking corporate hospitality packages.

"It would range from four guys in a company going over on a bit of a jolly right the way to a bespoke event for a company going in and out on a private charter, " said Mark Pinsent, managing director of 4U Hospitality in Limerick.

Pinsent said he has chartered an aircraft for one Irish company taking 28 clients over to Cheltenham for a day's racing at the festival. Chartering a plane costs in the region of 30,000. Apart from the flight itself, tickets for corporate boxes cost in the region of 800 per person. By the time space in the corporate boxes, lunch and champagne are factored in, Pinsent said the company will be looking at an outlay of more than 40,000 for a day at the races.

Cheltenham racecourse's commercial manager, Peter McNeile, said he expects up to 9,000 of the 55,000 punters attending each day to be tucking into three- or four-course lunches at the boxes and marquees set up for the festival. "This is a big piece of business in terms of hospitality revenue, " he said.

"It's all high-end. You don't do Cheltenham on the cheap, " said Michael O'Boyle of Irish company Absolute Events, which has sold out its allocation of corporate hospitality tickets and has for the past few weeks been taking bookings for next year's Cheltenham festival.

O'Boyle has chartered two aircraft for separate groups heading over to the races. Other groups using Absolute Events will fly on early-morning commercial flights as far as Birmingham, with a helicopter pick-up to chopper them to "one of the private manors in Cheltenham" for breakfast.

Following a light repast and a quick perusal of the form in the morning papers, they will board the helicopter again for the short flight to the track itself. Such a day trip, including a fourcourse lunch at the VIP marquee, costs between 1,400 and 1,700 per person, the price rising according to the prestige of the races on the particular day and the demand for tickets.

O'Boyle noted an increasing trend among Absolute Events' Irish Cheltenham clients to arrive on their own aircraft, using the corporate tour operator simply to book tickets, corporate boxes and accommodation. "Ireland has changed a lot. You have a lot of high-networth individuals who have an interest in Cheltenham, " he said.

Ian Statham, managing director of Gloucestershire airport, said the airport will handle "private jets, small turbo props and helicopters", all arriving from Ireland. The Cheltenham Festival is the busiest week of the year for Gloucestershire airport, the closest to the racecourse. "It's like Christmas at Harrod's for us, " Statham said.

Michael O'Leary said the festival will generate around 1m in ticket revenue for the airline, which will carry passengers from Ireland to Bristol, Liverpool, Birmingham and East Midlands airports en route to Cheltenham. Ryanair is even sponsoring a race.

This is an unusual move for Ryanair, which rarely enters into such marketing arrangements. "Cheltenham seemed a natural one for us, " O'Leary said. "It's a huge Irish/UK travel event. It's the next biggest thing to the rugby internationals in the entire year."

Ironically, however, the increasing tendency among Ireland's wealthy highfliers to procure their own aircraft has hit air traffic volumes between Ireland and Gloucestershire during the festival. "In the past few years it has slightly fallen off, " said Ian Statham. "A lot of people go just straight to the course with these really swish helicopters."

IRISH OWNERS HOPE TO BEAT BOOKIES AGAIN AFTER a vintage Cheltenham Festival for Irish-trained horses in 2005, a clutch of well-known Irish business people are hoping fortune will continue to shine this week.

Bookmaker Paddy Power, which expects to take 40m in bets over the four-day festival, lost 4m over the course of last year's race meeting. Irish punters tend to back Irish horses and, with nine Irish winners romping home at Cheltenham last March, the bookie was left nursing a painful loss and forced to issue a pro"t warning.

Property developer Lar Byrne, who recently paid 20m to acquire Chief O'Neill's hotel in Dublin's Smith"eld, will gleefully accept some of the credit for that pro"t warning. His prize equine asset, the legendary Hardy Eustace, won the Champion Hurdle for the second time in succession last year and is bidding to make it a hat-trick at this year's festival.

Other Champion Hurdle entrants keen to stop that happening include Ballymore Properties founder Sean Mulryan's Ambobo. Mulryan has other interests at Cheltenham which may also come good, including Forget The Past, an outsider tipped in some quarters as having the potential to upset the "eld in the Gold Cup. In order to do so, the horse will most likely have to get past Michael O'Leary's War Of Attrition.

"It's like the Olympics. Just having a runner is an achievement.

Having a winner, you've just died and gone to heaven, " said the Ryanair chief executive on what victory would mean for him.

Cathal Ryan, son of O'Leary's former boss Tony Ryan, will be pinning his hopes on The Railway Man. Elsewhere Brian Kearney, cofounder of Irish engineering company Project Management, will be hoping his horse, Moscow Flyer, can add the Queen Mother Champion Chase to its two previous Cheltenham victories. No national hunt meeting would be complete without a smattering of entries from proli"c owner JP McManus, whose prospective runners include Fota Island and Foreman.