MARLBOROUGH-BASED eventer Andrew Nicholson has undergone neck surgery after suffering a fall during the Festival of British Eventing at Gatcombe Park in Gloucestershire two days ago.

The 54-year-old New Zealander, a former world number one who has competed in six Olympic Games, fell from Cillnabradden Evo at the final fence on the British Open cross-country course.

The Wiltshire-based rider was initially taken to hospital in Swindon, but then transferred to Oxford's John Radcliffe Hospital, where he continues to be treated.

A statement updating his condition was released on behalf of the Nicholson family on Tuesday.

"Andrew Nicholson underwent surgery yesterday to repair the injury to his neck," it read.

"The surgery went well and his condition is stable. Andrew is comfortable and has full range of movement.

"His family would like to thank the many well-wishers."

Nicholson is among the most successful riders in eventing history.

He has helped New Zealand win three Olympic team medals - including bronze at London 2012 - and three World Championship medals, highlighted by a team gold in 1990 in Stockholm.

He has also enjoyed prolific success on the British and European circuits, winning the Burghley Horse Trials in Lincolnshire five times, as well as claiming victories at other major four-star events in Kentucky, Pau and Luhmuhlen.

His title collection additionally includes three British Open titles, while he has won the Barbury International feature class four years in succession on Avebury, a partnership that completed a Burghley hat-trick last September.