Strong, regal, confident (but not obviously amused): a self-portrait by Queen Victoria never shown in public before reveals how one of history’s more misunderstood monarchs really saw herself.

The sketch, which is to be exhibited next year, is from her personal sketchbook and shows the young Queen in her gown before a costume ball at Buckingham Palace in 1845.

Rather than the dowdy widow of popular recollection, it shows a woman who was fond of music, art and dancing, and who on her 19th birthday did not leave the ballroom until 3.50am.