Wartski, 14 Grafton
Street, W1 (020-7493 1141; www.wartski.com), May 11 to 21 (11am-5pm)
Exhibits include the silver chalice with which Charles took communion on the morning of his execution, and a number of pieces of jewelry that contain locks of his hair. Wartski also have a beautiful necklace made from silver pearls that belonged to Marie Antoinette. The queen gave them to the wife of the English ambassador during the revolution, who smuggled them out of France. Yesterday, the woman who worked at Wartski was so friendly that she took the necklace out of its case so my friend and I could inspect it closely and hold it! Well worth a visit.