On that day, the art teacher dragged girlfriend Elizabeth Tennant for a walk in torrential rain to look at blue plaques commemorating Richmond's history - a trip that he admits made his fair lady "more than a bit unhappy".
But the clouds lifted when his bedraggled belle looked up to see a sign that read as follows: "At this place Elizabeth Tennant, a resident of Bristol, agreed to a long awaited proposal from Chris Moss, an artist living in Richmond".
Mr Moss came up with the stunt because he was "nervous" about popping the question. "I suppose it was a bit presumptuous but she did say yes," he says. The plaque was fashioned out of cardboard but was so convincing that, as the couple drank champagne beneath it, tourists scratched their heads.
As the plaque melted away in the monsoon, even a ticking-off by a woman from the local Civic Trust could not dampen the happy couple's spirits.