King Charles III will hail the value of traditional alliances and international friendships at a time of "increasing pressures of conflict" in his Commonwealth Day message. The annual celebration of the Commonwealth, to be marked on Monday with a service at Westminster Abbey, will see the biggest gathering of senior royals since the arrest of his brother Andrew Mountbatten-Windsor. There will also be contributions at the service from performers including former Spice Girl Geri Halliwell-Horner and Strictly Come Dancing's Oti Mabuse. Against a backdrop of war in the Middle East and Ukraine, the King will commend the unifying force of the Commonwealth, a voluntary association of 56 countries. "It is often in such testing moments that the enduring spirit of the Commonwealth is most clearly revealed," the King's message will say. The King, who has campaigned for many years to protect the environment, will also reflect, in his written message, on pressures from "climate change and rapid transformation".…