Prince William warned footballers to watch the Buckingham Palace windows as the Queen's official residence staged the first football match in its 308-year history.
A match between two of England's oldest amateur teams took place in the 16ha gardens of the famous central London landmark as part of celebrations to mark the 150th anniversary of the Football Association. William, president of the FA, was on hand to oversee the event.
"This magnificent home, Buckingham Palace, is at the heart of the nation, and so there cannot be a more fitting setting to celebrate our national game, and to celebrate all of you," he told volunteers and guests including FA chairman Greg Dyke and former England striker Michael Owen.
William said he was "excited" to see "football on my grandmother's lawn", before joking: "One warning, though: if anyone breaks a window, you can answer to her." Civil Service are the sole surviving football club from the 11 teams who founded the FA in central London in 1863. Polytechnic were formed in 1875. Polytechnic prevailed in the Southern Amateur League game, winning 2-1.