Surprise Birthday Cake!

I'm not sure if you can guess what the celebration is from the cake??

My friend and I were celebrating another significant birthday this year, so we had a party tonight. My friend has already reached this milestone but I have to wait until November. We had a party 10 years ago for a previous significant date.

The cake was a really lovely suprise from one of our retired colleagues who's cake we've sampled on many occasions. In fact they've been blipped before:

Wimbledon cake
Another celebration cake