All of these are true laws in the UK which have never been rescinded so they are technically still legal....
It is illegal to die in the Houses of Parliament.
It is illegal to enter the Houses of Parliament wearing a suit of armour.
Taxi drivers are required to ask all passengers if they have smallpox or the plague.
Any person found breaking a boiled egg at the sharp end will be sentenced to 24 hours in the village stocks
it is illegal to eat mince pies, in England, on Christmas day, as in the 17th century Oliver Cromwell banned Christmas pudding, mince pies and anything to do with gluttony.
It is illegal to fire a cannon close to a dwelling house (Met Police Act 1839
The use of any slide upon ice or snow is illegal (Town Police Clauses Act 1847);
It is prohibited to drive cattle through the streets of London (Metropolitan Streets Act 1867).
it is regarded as an act of treason to place a postage stamp bearing the British king or queen's image upside-down
A pregnant woman can legally relieve herself anywhere she wants
The head of any dead whale found on the British coast automatically becomes the property of the King, and the tail of the Queen
It is illegal not to tell the tax man anything you do not want him to know, but legal not to tell him information you do not mind him knowing.