Leading Light has cemented his position as favourite for the Gold Cup at Royal Ascot with a perfect start to his four-year-old campaign in the Vintage Crop Stakes at Navan.

At his first start since his unplaced effort in the Prix de l'Arc de Triomphe in October, Leading Light took up a position behind the front-running Royal Diamond with a half a mile (800m) to travel.

With the latter sticking to the far rail, Joseph O'Brien's mount came down the middle in company with Pale Mimosa.

Leading Light went clear in the final 200 yards to win with three lengths in hand from Royal Diamond, who held on well to take second.

"You'd have to be very happy with him, you couldn't be happier really," trainer Aidan O'Brien said.

"We haven't seen the bottom of him yet, at the end of two miles at Ascot last year (Queen's Vase) he didn't seem to be stopping so we will look forward to that (Gold Cup) and he could run in the Saval Beg before that."

Coral and Ladbrokes cut Leading Light to 2-1 favourite for the Ascot showpiece, with RaceBets going 9-4.

O'Brien doubled up when Leading Light's full-brother John Constable (5-4 fav) stayed on strongly in the Excelebration Maiden.

Like his brother last year, he could be aimed at the Queen's Vase at the Royal meeting.