‘Damn! This is a Caravaggio!’: the inside story of an old master found in Spain

Art dealer Giancarlo Ciaroni attempted to buy painting listed at 1,500 for 500,000 - but discovered bewildered owners already had two offers of 3m

It took all of six minutes for Massimo Pulini to realise that the small oil painting due to go under the hammer in Madrid earlier this month with a guide price of 1,500 (1,300) could be worth millions.

At 9.48pm on 24 March, Pulini, a 63-year-old professor at the Bologna Fine Arts Academy, received an email request for an evaluation. Sent by an antiques dealer and friend of Pulini's, it included a photo of a luminous oil painting of the scourged Christ.