OLYMPIC and European individual champion Michael Jung put himself in pole position to land eventing’s richest prize - a £240,000 Grand Slam jackpot - by taking charge of this year’s Mitsubishi Motors Badminton Horse Trials on day one.

A stunning dressage score of 34.4 penalties aboard his London 2012 double gold medal-winning horse La Biosthetique-Sam gave 33-year-old Jung a clear overnight lead from his fellow German Andreas Ostholt, riding So Is Et, with Sussex-based Francis Whittington currently heading the British challenge in third aboard Hasty Imp.

The Rolex Grand Slam is awarded to any rider who wins consecutive Burghley, Kentucky and Badminton titles. So acute is its degree of difficulty that the only rider who has accomplished it is Britain’s Pippa Funnell 13 years ago.

Jung, though, already has Burghley and Kentucky silverware in the bag and was Badminton runner-up three years ago, but he has now given himself an outstanding chance of going one better just three months before he defends his Olympic title in Rio.

“I think about it (the Grand Slam), yes,” Jung said.

“It’s always in the head, but I would like to ride as normal, as if it is any other competition here.”

British star Oliver Townend, meanwhile, who lies 11th overnight with Armada, called for an overhaul of the Badminton rider draw process after he was again handed a number one slot.

Former Badminton champion Townend believes it is “beyond a joke” that he has been drawn first to go four times in the event’s last six runnings.

The number one position - there are 77 starters at Badminton this year - is sometimes seen by riders as a disadvantage in terms of gaining low dressage marks.

“The draw is beyond a joke,” Shropshire-based Townend said. “To say it’s a draw is nothing but an insult to everybody’s intelligence. I have been number one too many times, now.

“There is absolutely no question of a doubt it (the draw) should be done in public, and why not make it a public spectacle. We are at the biggest event in the world.”

A Badminton spokesman said: “The draw is done in a dead straight way.

“Oliver always enters two horses, and there is only a pool of about six riders who do so, so the odds of him being number one are fairly high.

“It is a coincidence he’s been first a few times, but there is nothing untoward in it at all. Unlike an FA Cup draw, the draw for Badminton would not be a public spectacle, however it was done.”

Marlborough-based New Zealanders Jesse Campbell (fifth) and Jock Paget (ninth) were also inside the first-day top 10, on Kaapachino and Clifton Lush respectively.

Dressage continues on Friday, when starters include former world champion Zara Tindall with High Kingdom, and her fellow British Rio contenders Gemma Tattersall, Laura Collett, Nicola Wilson and 20-year-old Badminton debutant Emily King.