Police officers and staff from the Redwing Horse Sanctuary were helping with the operation in Amersham, Buckinghamshire.

Thames Valley Police arrested one 44-year-old man on suspicion of assaulting a police officer and criminal damage.

RSPCA found 31 dead horses, ponies and donkeys when they were called to the site over the weekend. The animals had been neglected and left where their bodies had fallen, said animal welfare workers.

They removed 14 animals immediately and three more were in such a poor condition they had to be put to sleep on veterinary advice.

The remaining 84 horses are now being removed and taken to sanctuaries by the RSPCA, Redwings Horse Sanctuary and the International League for the Protection of Horses.

A spokeswoman for the RSPCA could not say if the horses belonged to a private owner or a commercial concern. But she said that it was likely that the charity would seek a prosecution of the horses' owner.

A spokeswoman for Redwings Horse Sanctuary said: "Redwings Horse Sanctuary has travelled to rescues on many occasions but rarely sees cruelty so far advanced that equines are seemingly forgotten and literally left to die.

"All organisations involved in this rescue were deeply concerned about the welfare of the remaining and surviving horses, ponies and donkeys.

"Redwings are hopeful that a prosecution of the owner will follow - for both the deceased equines and those surviving that were considered to be in an unacceptable condition - but it is too early to comment on this in full."