However, Henry VII backdated the start of his reign to 21 August, the day before the battle, which enabled him to prosecute anyone who had fought under his rival and execute them for treason.

This was highly controversial, since it meant that anyone who fought for the rightful king against a usurper would be at risk of execution if they lost, and might undermine their courage and loyalty.

Nevertheless, Henry VII had his way as the Parliament of England was in no position to oppose him, although later that year a general pardon was issued to those who had fought for Richard III.

[3] However, in 1495, Henry VII's position on the throne was sufficiently secure that he could afford to allow Parliament to pass a bill to prevent the treason laws from being abused in this way.

[citation needed] In New Zealand, the Crimes Act 1961 provides that obedience to the laws of a person with "possession de facto of the sovereign power" is protected from criminal responsibility.