Kim Roberts, 58, who briefly worked as housekeeper to Gloria, the Dowager Countess Bathurst, 87, in her homes in Cirencester and London, was sentenced to three years in prison by Gloucester Crown Court on May 7.
Judge William Hart said she had betrayed the trust of her employers through "avarice and dishonesty" but added that it was thanks to the honesty of the art and antiques dealers involved in the case that all the stolen property Roberts tried to sell was recovered.
Evidence supplied in the case by members of the trade - some acting undercover - can now be reported following sentencing.
In early July 2013 Michael MacDonald, co-founder of online valuation firm Antique Vault, who specialise in negotiating private treaty sales, was contacted via his website by a lady looking to sell a Ben Nicholson still life. She said her name was Kim Roberts-Fleming and claimed to be a member of the famous banking family.
Potentially this was a "dream find" - a rare transitional work by Nicholson c.1945 with a provenance to the 1956 British Council exhibition in India - but a meeting with the 'owner' at the Lansdowne private members club in Mayfair left MacDonald feeling uneasy.
"On meeting Roberts she became increasingly pushy and kept changing goalposts, claiming she had offers elsewhere," he said. A London auction house had already seen the picture and, valuing it at £200,000, had courted the vendor with a recent VIP trip to the races. MacDonald was shown photographs of Roberts presenting a winners' trophy at the event.
Changing Story
MacDonald convinced her to leave the picture with him. He took it first to another London auction house specialist (who, on balance, deemed it a fake) and then to a number of art dealers who were confident it was 'right' and offered sums into six figures.
"If I had been greedy I could have fallen for it but I was unhappy at Roberts' push for a quick sale. Over a period of about three weeks the story of how she obtained the picture kept changing. I decided to string her out as long as possible and research the background of the picture."
Period photographs supported its illustrious provenance but a call to the dealers Lefevre Fine Arts, whose sticker appeared to the back of the painting led to the unearthing of a more troubling recent history.
Alexander Corcoran of Lefevre, who was a family friend of the Bathursts, contacted the countess who checked and found the Nicholson was missing. She also realised that other property including a Picasso sketch had also gone. The police were contacted.
When MacDonald met with Corcoran and members of several police forces at the Lansdowne the following month, he was - heard the court - "clearly very shaken" upon realising the deception and immediately agreed to participate in the sting operation which led to Roberts' arrest later that day.
The Art and Antiques Unit at New Scotland Yard said he took to the role "like a duck to water and seemed to be enjoying [himself] throughout".
Prosecutor Ian Dixey also told the court of the professionalism shown by a dealer in Honiton.
"It is significant that on August 23, after her arrest, Roberts visited Katherine Spencer of Otter Antiques in Devon and took with her a number of items of silver which she said were hers.
"That lady very properly asked for her identification and also took photos of the property and also took details of the defendant's Volvo car."
The case underlined the importance of conducting due diligence in every transaction.
"If I had bought and sold the picture my reputation could have been in ruins and I could have been liable for a great deal of money," said MacDonald.
The Nicholson and the Picasso, plus other valuable works of art found at her home in Colyton, Devon, have now been returned but police believe other items sold by Roberts - perhaps across a number of years - remain at large.
Charges and Sentence
On April 8, Roberts had admitted three charges she had previously denied - including burgling the countess' Kensington home between April and May 2013. She also admitted stealing a car from a previous employer, the interior designer Emily Olympitis.
At a hearing last year, Roberts said she had taken the art and antiques but had claimed she was guilty only because the property was put in her car by mistake. Her barrister Simon Burns told the court she had now abandoned that claim and fully accepted her responsibility.
Roberts was released on bail until May 7 to allow for the preparation of a pre-sentence report by the probation service but had been told to expect a lengthy prison sentence.
On May 7 Judge Hart passed a sentence of 30 months jail for the theft of the paintings, 15 months concurrently for the burglary of the London flat, four months consecutively for the theft of the car and two months consecutively for defrauding an employment agency with a fake date of birth. He also passed four weeks concurrently for breach of a previous suspended sentence - a total of three years.
