Ruth Edge (pictured) holds the lead at the half way point in the cross-country of the Mitsubishi Motors Badminton Horse Trials.

Ruth had to ride determinedly at times on last year’s British open champion Mayhem III — not least at the Lancer Village (fences 3, 4 and 5), where she did a great save after nearly falling off — but came home just four seconds over the optimum time.

“He’s never normally a strong horse, but he towed me to fence 3 and my stride disappeared,” she said on Radio Badminton. “I didn’t have the same control as I have in the past with him, but he was as honest as the day is long.”

Ruth is 6.4 penalties ahead of William Fox-Pitt, who lies second on last year’s Luhmühlen winner Macchiato, who went clear inside the time on his Badminton debut.

“He was foot perfect — that was probably the best four-star ride I’ve ever had,” said William.

Australian Sam Griffiths is third on last year’s Saumur winner Happy Times, who is only 10, while Irish first-timer Elizabeth Power is just behind him after a penalty-free round on Kilpatrick River.

“It was nice to have my first experience at Badminton on a blood horse — I wouldn’t have forgiven myself if I’d had time-penalties on him,” said Elizabeth.

As the riders predicted, the ground is riding fast and eight competitors have finished inside the optimum time so far.

Emily Baldwin is the highest profile casualty of the course so far. She was fourth after dressage, but in making sure Drivetime did not run out at the fence in the middle of The Lake — as he did last year — she lost impulsion and he ground to halt. Emily then retired.

Zara Phillips pulled up Ardfield Magic Star, who went lame on course.

Dressage leader Karin Donckers starts at 4.16pm on Gazelle De La Brasserie.

RESULTS AT 1.15pm

1. Ruth Edge on Mayhem III (GBR) 45.4
2. William Fox-Pitt on Macchiato (GBR) 51.8
3. Sam Griffiths on Happy Times (AUS) 53.3
4. Elizabeth Power on Kilpatrick River (IRL) 54
5. Daisy Dick on Spring Along (GBR) 57
5. Caroline Powell on Lenamore (NZL) 57.5

Log back on to www.horseandhound.co.uk later for an end of day update.

Don’t forget to buy H&H next week (14 May) — our 15-page Badminton report will include comments from Carl Hester, Mark Todd and Tina Cook, plus cross-country course analysis and plenty of colour photographs.