Caroline Powell’s promising four-star ride Mrs Tilly has been put down after a sudden, mysterious illness.

The 11-year-old had been “happy and hacking” on Friday, but when Caroline returned from winning the advanced at Burgham on Saturday (24 March) with Onwards And Upwards, Mrs Tilly was not well.

A statement from the vets on nzequestrian.org.nz said: “From the first report of very mild signs of disease on Friday, her medical condition deteriorated rapidly through Saturday afternoon and evening in spite of prompt, intensive veterinary care.

“By lunchtime on Sunday, with her condition continuing to deteriorate, the difficult decision was made to put her to sleep.

“The precise nature of the conditions affecting Mrs Tilly has not been identified, however the nature of her symptoms were consistent with an encephalitis [inflammation of the brain] of some kind. This type of disease is extremely rare in the UK.”

Mrs Tilly, by the 15.2hh thoroughbred-riding pony stallion Romany Jojo, belonged to Roy and Fiona Martin and Fiona’s daughter Mila Neil Martin. She was produced to two-star level by Mila, finishing ninth at Burgie CCI** and 12th in the under-21 national CCI** championship at Weston Park in 2008.

Caroline Powell took on the ride in 2010 and the pair were fifth at Blair Castle CIC*** that year. In 2011, Mrs Tilly was 15th at Luhm ¼hlen and completed Burghley (pictured above) with one stop across country. She had run twice this year, finishing sixth in open intermediates at both Isleham and Lincolnshire. Mrs Tilly was 16th on the waiting list for Badminton, but Caroline had planned to take her to Kentucky for her spring four-star outing.

Kelso-based Caroline said: “We are all devastated with the loss of Mrs Tilly, the suddenness and extremity of it is shocking. She was one of the gutsiest, easiest, coolest little bay mares to go cross-country on, and she was clocking up some impressive dressage performances and deserved her listing for the New Zealand team.

“She will be sorely missed by the whole team here – she was ready to make her mark.”