The lorry was parked on a busy road outside the funeral directors in Church Road, Stainforth, Doncaster, on Wednesday (7 October) and was taken between 11am and 12pm.
The owner, Karen Bassett, has provided a horse-drawn service for funerals for almost 13 years.
Karen is also a leading British carriage driver. She has competed as part of the British team at several world four-in-hand carriage driving championships.
“We drove the horses back to the funeral directors after the funeral, but when we arrived the lorry was gone,” she told H&H.
“There was glass on the floor where they had smashed the window to get in.
“We were left stood in the pouring rain with the horses with no food or water while we waited for backup transport.
“I went into shock — I couldn’t believe what had happened. It was a busy road and broad daylight.”
The horsebox, worth £15-20,000, was purpose built by Tristar with a MAN chassis and a 23ft-long aluminum body.
“There was quite a lot inside it. As it was raining we put capes on and left our best funeral jackets in the lorry,” said Karen.
“There were also lamps and all our personal belongings inside.”
Karen has been scouring the area looking for the horsebox and is desperate for any leads.
In the meanwhile she will be borrowing transport from friends so she can travel to funerals she is booked to attend with her horses.
“People have been so kind and I have been taking them up on their generous offers — if I can’t do the funerals I will go out of business,” she added.
Police enquiries are ongoing. Anyone with information about the horsebox’s whereabouts should call police on 101 quoting incident number 502 of October 7 2015.