A huge surge in electricity demand marked the end of television coverage of Kate and William's procession to Buckingham Palace.
The 2,400 MW boost as cameras switched back to television studios at 12.40pm was equivalent to nearly one million kettles being boiled at once.
It was the fourth largest surge due to a television programme yet experienced by the National Grid, outstripping that of 1,800 MW seen during the marriage of the Prince of Wales and Diana, Princess of Wales, in 1981.
Earlier in the day, demand on the grid plunged as millions were glued to their television screens as the drama unfolded.
The National Grid recorded a 1,500 MW drop in demand as Kate travelled by car to Westminster Abbey and a 500 MW drop as the couple exchanged their vows.
There was a 1,000 MW surge in demand when the service resumed after the vows, and an 800 MW surge as the couple moved to sign the register.
The demand then dropped again by 1,300 MW during the procession through the cathedral, out on to the steps and during the procession to the palace.
The biggest drop in demand, of 3,000 MW, occurred as the couple appeared on the balcony of Buckingham Palace and the RAF staged the flypast.
John Carnwath, power system manager in National Grid's control room during the ceremony, said: "It's been a fascinating day to work in our control room, seeing the huge impact on electricity demand of millions of people across Britain being brought together by William and Kate's wedding."
The top three surges in demand are: 2,800 MW at the end of the penalty shoot-out for England's World Cup semi-final against West Germany in 1990; 2,600 MW after a 1984 episode of The Thornbirds; and 2,570 MW surge at half-time during England's semi-final match against Brazil in the 2002 World Cup.