I have to admit that I was surprised when I started noticing how superstitious the British are. I think this came about when I was planning our wedding.
Here are few other ones that have crept up over time:
Do not put new shoes on a table because it means someone will die soon. This is because they used to buy new shoes when someone passed away to prepared them for their journey.
When you buy a pram (stroller) for an unborn baby, it is unlucky to bring in the house before the baby is born.
Touch wood. Same as knock on wood.
Groom cannot see the bride in her wedding dress before they are married.
Magpies on their own are thought to be unlucky. There is a rhyme about magpie “One for sorrow, Two for joy, Three for a girl, Four for a boy, Five for silver, Six for gold, Seven for a secret never to be told”. In some parts of England, they believe you should wave or take off your hat.