Apple Blossom by George Clausen was one of the paintings stolen
A couple said thieves who tied up their house-sitter during a £2m raid at their Somerset home were "animals".
Deborah Barnjum, 47, was tied to the banisters at the home of Esmond and Susie Bulmer, members of the Bulmers cider family.
Ms Barnjum was discovered the next day by her sister who had come looking after she was not answering her mobile.
The house-sitter was letting the family dog out before going to bed when she was ambushed by four men on Friday.
The Bulmers, who were on holiday in Barbados, were called by police who told them they had had the "most terrible burglary".
The gang-of-four also stole antiques, a safe containing jewellery, a green Mercedes 220 and 15 paintings including Endymion by George Frederic Watts and Apple Blossom by Sir George Clausen.
Mr Bulmer, 73, said some of the items were of high monetary value but others were of sentimental value.
"The most important thing is to catch these men for what they did to Deborah. These people are animals."
Mrs Bulmer, 67, said that when they arrived back they were unable to get into the house as it had been declared a crime scene.
"Deborah could have been killed, these men are evil. She was very stiff and could hardly walk after being tied up for so long.
"They tied her to the banisters in the most uncomfortable position and left her there, putting her phone tantalisingly inches away so she couldn't reach it when it was ringing constantly."
Avon and Somerset Police are appealing for any information about the robbery which happened at The Pavilion in Redlynch, near Bruton on 20 March.