HRH The Duke of Edinburgh, 1983 by Bryan Organ A spokesman said: “Having grown up surrounded by the Royal Collection, The Prince of Wales has enjoyed a life-long passion for art and, as chairman of The Royal Collection Trust and patron of several arts charities, has promoted the creation and understanding of art worldwide.” The Prince of Wales is to put favourite family portraits from the walls of his own home on display in a celebration of his birthday, including a touching portrait that “reminds me of the essence” of his beloved grandmother.The Prince said the oil sketch of Queen Elizabeth, the Queen Mother, “brilliantly captured” the likeness of the woman he adored, and is usually kept at his London residence of Clarence House.The study, by Michael Noakes, is among five family pictures from the Prince’s personal collection that will go on display at Buckingham Palace’s Summer Exhibition, where more than 100 works will be offered as part of a special birthday exhibition.The Prince, who turns 70 this year, has also selected artworks from the Royal Collection and by artists supported by three charities he works with for the show, entitled “Prince & Patron”.The portraits include a never-before-seen pencil sketch of the Duke of Edinburgh by Bryan Organ. The final portrait, completed in 1983, hangs in the National Portrait Gallery. It was produced by Michael Noakes, who died this year, as a study for a painting marking the silver wedding anniversary of the Queen and Philip in 1972.In a message recorded for visitors at the palace, Charles says: “I acquired it from the artist as I felt it brilliantly captured her likeness and, above all, reminds me of the essence of her personality.”I admire it often when in residence at Clarence House.”It will join an oil sketch, HM The Queen by Michael Noakes, purchased by the Prince of Wales shortly after it was completed 1973. They usually hang in Highgrove, the private residence of Charles and the Duchess of Cornwall, while the double portrait commissioned in 2009 is displayed in the National Portrait Gallery.A sketch of the Queen Mother wearing Queen Victoria’s diamond jubilee brooch is also to be shown. Preparatory sketch of Prince William, 2009 by Nicky Philipps Two preparatory oil sketches of Prince William and Prince Harry in their Blues and Royals Household Cavalry regimental uniform by Nicky Philipps are also going on public display for the first time. Preparatory sketch of Prince Harry, 2009 by Nicky Philipps. The majority of the exhibition will be made up of works from artists supported by three of the Prince’s charities: the Royal Drawing School, The Prince’s Foundation School of Traditional Arts, and Turquoise Mountain.The exhibition can be viewed as part of a visit to the summer opening of the state rooms at the palace from July 21 to September 30. Want the best of The Telegraph direct to your email and WhatsApp? Sign up to our free twice-daily Front Page newsletter and new audio briefings.