A man goes to his doctor complaining about headaches. The doctor explains it's due to blood flow, and he has three options.
“I could remove half of your heart to limit the blood flow, that should fix it.”
The man cries out “no, I don't want to be a Tory supporter!”
“Well then, I could remove half your brain to reduce the pressure, that should also do the trick.”
The man cries out “no, I don't want to be a Labour supporter!”
“Well the final option is for me to remove your testicles to fix the hormone imbalance.”
The man thinks for a moment, and says “okay, I'll go with that option.”
The doctor smiles and says “I knew you were a Lib Dem.”