Animal welfare workers in eastern England are investigating why two sick, underweight ponies were dumped in a wet, muddy field.

The pair of fillies were just hours from death when an inspector from the Royal Society for the Prevention of Cruelty to Animals acted on an anonymous tip-off and found them in Longstanton, near Cambridge, on March 3.

They were both severely underweight , there was no grazing in the field and they had just been left to starve to death, the inspector, Richard Lythgoe, wrote in a statement.