Ros Canter is on the brink of making eventing history as the first rider to win MARS Badminton Horse Trials three times on the same horse.

She and the magnificent Lordships Graffalo put up a supremely impressive cross-country performance, adding no penalties to their leading dressage score of 23.7. This gives them one show jumping fence in hand for victory tomorrow.

‘My cross-country round wouldn’t have looked so perfect if I hadn’t been on “Walter”,’ Ros admitted, a reference to only returning to the saddle during February after giving birth to her second daughter, Seneh, in January. She was quick to pay tribute to her team at home, and to her ‘amazing’ mother, Heather.

‘I feel incredibly grateful to have a horse like Walter when I am not at my fittest. He is always light in his gallop and that allows me to be one of the fastest in the world.

‘The challenge this week has been more mental, and a matter of working out timings around feeding the baby and having time to myself, as I usually do at a major competition.

‘The crowds were amazing and I could hear them shouting “Go Walter!” What a lucky person I am to have a horse like that.’

Ros heads a British one-two-three. World number one Harry Meade rose nine places to the runner-up spot on the second of his three rides, Annaghmor Valoner, and Sarah Bullimore leapt 16 places to third on her home-bred 10-year-old, Corimiro.

In addition, Britain’s Katie Magee, last year’s best first-timer, is lying fourth on Treworra; Ireland’s Lucy Latta is fifth on RCA Patron Saint; and New Zealander Tim Price, the world number two, is sixth on Falco, despite battling with a injury to his clavicle.

Switzerland’s Nadja Minder, riding the 19-year-old Toblerone, was the only first-timer to get around and she is now in 14th place.

After a thrilling and successful day’s sport, there were 45 completions from the 59 cross-country starters, with 34 clear rounds and seven inside the optimum time of 11 minutes 30 seconds.

Harry Meade, who has now clocked up 17 cross-country rounds at Badminton, is also lying 22nd on his cross-country pathfinder Et Hop Du Matz, but he tipped off his third ride, Cavalier Crystal, when she trod on herself at fence 22, having been up on the clock.

‘I’ve had quite a busy day,’ he admitted. ‘Annaghmor Valoner is a lovely mare. She has historically lacked self-belief and, because of that, I have always had a soft spot for her.’

Harry paid tribute to Sarah Bullimore’s achievement in producing a home-bred horse to Badminton level. ‘Corimiro is a phenomenal horse,’ she said. ‘He is the horse I get up for in the morning and the reason I am still competing. Every phase is a pleasure. He just wants to do the job.’

The final horse inspection takes place at 8.30am tomorrow, with the lower placed horses jumping at 11.45am and the top 20 at 2.45pm for what promises to be a thrilling finale.

Ros Canter explained she and her family were planning to enjoy their evening. ‘What will be will be tomorrow,’ she said. ‘You have to remember that I am only human and Walter is only a horse.’

Follow the competition on Badminton TV and Radio Badminton. The cross-country highlights and top 10 riders show jumping will be shown on BBC 2 at 1.45pm tomorrow.