In 2019 it launched a crowdfunded challenge to the prorogation of Parliament by Boris Johnson's Conservative government, which was ultimately successful.

The prorogation was ruled unlawful by the Supreme Court,[7] but by this time Johnson's government had pushed through their Brexit deal so the issue was moot.

However, the £200,000 raised enabled Good Law Project to hire more staff and launch other fundraisers to take on more cases.

In the 2022 case of Good Law Project & Anor, R (On the Application Of) v The Prime Minister & Anor [2022] EWHC 298 (Admin), the High Court was critical of the Good Law Project "drafting its objects clause so widely that just about any conceivable public law error by any public authority falls within its remit" and was not convinced that "such a general statement of objects" could confer legal standing upon the company; the Court added that it could not be supposed that the company had "carte blanche to bring any claim for judicial review no matter what the issues and no matter what the circumstances."

[8][9] The Good Law Project challenged the Secretary of State for Health and Social Care, claiming that the COVID testing contracts with Abingdon Health were unlawful because they were not advertised nor open to competition, and the correct procurement process was bypassed.