The challenge stemmed from a 2020 decision by the Executive Committee for the Protection of Royalty and Public Figures (Ravec) to reduce Harry's security protection after he stepped down as a senior royal.
Harry's legal team argued the decision put his life at risk, but the court found his arguments, while compelling, lacked a legal basis to overturn Ravec's decision.
The court deemed Ravec's decision to provide different levels of security based on Harry's location (inside or outside the UK) as reasonable.
Harry could potentially appeal the decision to the Supreme Court.