The British Army has played a central role in the long history of conflict and co-operation between Britain and Ireland. Here we explore some of the key moments in this difficult but fascinating story.
Fought between 1919 and 1921, this was a guerrilla and sectarian conflict involving Irish republicans, Ulster loyalists and British government forces. It brought about the creation of Northern Ireland and the Irish Free State.
In 1798, an underground republican group known as the Society of United Irishmen instigated a major uprising against British rule in Ireland. Although the revolt ended in total defeat for the rebels, it marked a significant watershed in Irish history.
Today, the UK government makes financial provision for the spouses and partners of soldiers who have died in the line of duty. But this has not always been the case, and there have been a number of changes along the way.
In 1945, British troops occupied Germany alongside their wartime Soviet allies. But growing East-West tensions soon evolved into the Cold War. For the next four decades, soldiers in Germany prepared to face an attack by the Warsaw Pact.
Following their victory over Nazi Germany in 1945, the Allies were faced with administering a country in ruins. British soldiers had a leading role in this, helping to hunt war criminals, rebuild industry and help displaced persons.
In September 2000, British troops undertook a daring hostage rescue operation in the war-torn West African country of Sierra Leone. They successfully freed five British soldiers who had recently been captured and around 20 civilian prisoners.
One of the most famous counter-terrorism operations in history took place in 1980. Gunmen overran the Iranian Embassy in London and took hostages, but the crisis was resolved when the building was stormed by the SAS.
In 1660, the monarchy was restored when Parliament invited King Charles II to take the throne. Although the military played a crucial role in his return, the King soon established a new force - the British Army.
Fought between 1642 and 1651, these wars were primarily disputes between Crown and Parliament about how the British Isles should be governed. But they also had religious and social dimensions, and witnessed the creation of the first national standing army.