John Hampden was a prominent puritan MP and had been imprisoned briefly for refusing to pay the forced loan. He was a friend of Sir John Elliot
In November 1637, he was taken into court by Charles for refusing to pay ship money. Hampden's lawyer, Oliver St John claimed Parliament could have been called to grand a subsidy between the time it was called and enforced
This was a subtle attack on the king as this did not challenge his right to take action in an emergency or decide if it should not exist- it was a question of timing
Judgement took 6 months to reach and ended in 12 judges ruling 7 to 5 in Charles' favour
However, this became a moral victory for Hampden as complaince fell from 80% in 1638 to 25% in 1639 causing a debate over constitutional issues nationally