Art galleries must improve their security following recent high-profile raids, a leading investigator has said.
A Cairo gallery had no alarms working when a Vincent Van Gogh painting worth $50m (£32m) was stolen on Saturday.
"This doesn't surprise me at all," said Charles Hill, a former detective with the Metropolitan Police's art squad.
He said the "same sorry saga" was seen in May when thieves targeted the Museum of Modern Art in Paris, where the alarm had been out of order for weeks.
Five works by artists including Picasso and Matisse, worth just under 100m euros (£86m), were taken in that theft.
At Cairo's Khalil Museum, only seven out of 43 security cameras were working when thieves cut the Van Gogh painting from its frame.
Egypt's prosecutor-general Abdel-Meguid Mahmoud described the museum's security measures as "for the most part feeble and superficial".
Mr Hill told BBC Radio 4's Today programme: "If you just go back three months to Paris and the Museum of Modern Art, [it was] the same sorry saga of no alarms, or few alarms, and cameras that don't work and on and on.
"It's a wearying saga and you think, why don't directors of museums and the boards of trustees take security more seriously?
"Certainly in Cairo and Paris you've got two prime examples of people being indifferent to the need to protect their paintings."
Somebody with "inside information" about the Cairo museum's lax security could have taken advantage of the situation, he said.
But the painting was unlikely to have been stolen to order for a collector, he added.
The Van Gogh painting - known as both Poppy Flowers and Vase And Flowers - measures 30cm by 30cm (1ft by 1ft).
Depicting yellow and red flowers, it is believed to have been painted in 1887, three years before the artist's death from a self-inflicted gunshot.
The painting was previously taken from the same museum in 1978, but recovered a decade later in Kuwait.
The Mahmoud Khalil Museum also holds works by Monet, Renoir and Degas.