Sources in the link
Can I claim self-defense if I hit someone first?
"There is no rule in law to say that a person must wait to be struck first before they may defend themselves" UK.
"You must have honestly and reasonably believed that you had to use force to protect yourself from the imminent unlawful use of force by another. If a Judge or Jury finds that your belief was honest and reasonable, it means you were allowed to act at right away to defend yourself. You DONāT have to wait until the other person touches you, grabs you, or hits you to hit them."
Can I claim self-defense if I hit someone first?
"There is no rule in law to say that a person must wait to be struck first before they may defend themselves" UK.
"You must have honestly and reasonably believed that you had to use force to protect yourself from the imminent unlawful use of force by another. If a Judge or Jury finds that your belief was honest and reasonable, it means you were allowed to act at right away to defend yourself. You DONāT have to wait until the other person touches you, grabs you, or hits you to hit them."