Video report by ITV News Correspondent Rebecca Barry
A famous Renaissance painting thought to be an imitation of Sandro Botticelli's Madonna of the Pomegranate has been revealed to be, in fact, a rare piece from the artist's own workshop.
The discovery was made while the painting was being cleaned by English Heritage conservators who scrapped off dirt and more than a century of yellow varnish, revealing the painting's true colours.
The painting shows Madonna and the Christ Child - who hold a pomegrante to symbolise Jesus' future suffering - flanked by four angels, was assumed to be a fake as it was similar and differed to the original.
Yet X-ray testing, infrared studies and pigment analysis revealed that the painting, with its vivid reds, blues and golds, came from Botticelli's Florence workshop.
It was also noted that changes to the final composition had been made, something which does not often happen in the creation of copies.
The piece - which can be found at Ranger's House in London - was assumed to be an imitation by an unknown artist because it varied in detail to the original and because of the thick yellow varnish that concealed the quality of the work.
Rachel Turnbull, English Heritage's senior collections conservator, explained that after consulting with experts at the Victoria & Albert Museum and the National Gallery, "we are finally able to confirm that Madonna Of The Pomegranate is from the Florentine workshop of master painter Sandro Botticelli...
"Being able to closely examine and conserve this painting for the first time in over 100 years has really given us the chance to get up-close and personal with the paintwork.
"I noticed instantly that the painting bore a striking resemblance to the workshop of Botticelli himself; stylistically it was too similar to be an imitation, it was of the right period, it was technically correct and it was painted on poplar, a material commonly used at the time.
"After removing the yellowing varnish, x-ray and infrared examination revealed under-drawing, including changes to the final composition uncommon in straight imitations."
What does the image show?
The painting shows Madonna and the Christ Child flanked by four angels.
The title refers to the pomegranate that is held by the Madonna and Child to symbolise Christ’s future suffering.
The angels worship the Madonna and child with lilies (a symbol of Mary’s purity and virginity) and garlands of roses (a symbol of Mary’s love of God) whilst holding books of prayer.
Botticelli's original Madonna of the Pomegranate (Madonna della Melagrana) from 1487 is in the Uffizi Gallery in Florence, Italy.
Who was Sandro Botticelli?
Alessandro di Mariano Filipepi (1445-1510) was one of the greatest painters of the Renaissance in Italy.
He ran a successful workshop in Florence from 1470, employing a number of assistants who would execute large parts or even whole panels of his paintings to help him meet demand.
It was not unusual for popular paintings by Botticelli to be commissioned again by other patrons, but these were often reduced in size, composition or detail by the master and his workshop assistants to fit a smaller budget.
That was the case for this painting, which is the closest copy to the original.
The painting will be officially revealed when it goes on display at Ranger’s House in Greenwich on April 1.