When former One Nation senator Rod Culleton first confronted the High Court challenge that would end his brief political career, he memorably remarked that constitutional law was "right up my veggie patch".

The wheat farmer-turned-legal crusader will need every bit of constitutional acumen to prove his latest claim of injustice: that the entire country's legal apparatus is invalid because references to the Queen have been unlawfully removed.

Former senator Rod Culleton refers to himself as 'senator in exile'. Credit:Alex Ellinghasusen

In a bizarre letter to his former Senate colleagues, Mr Culleton said he had uncovered "criminal and civil misconduct, including abuse of power, by some of our country's highest lawmakers, authorities and judges".

A 15-page dossier delivered to Prime Minister Malcolm Turnbull and others claims, among other things, that: