Is it permissible to tailor police uniforms in a company that sews clothes, knowing that the state is secular and governs by other than what Allah has revealed, and its police force is subordinate to it?

The original ruling is that it is permissible for a Muslim to engage in buying, selling, and leasing with a non-believer, as long as it does not involve aiding in a sin.

As for tailoring clothes for policemen, there is no harm in it, provided that the clothes do not contain polytheistic symbols or forbidden images, or if they are women's clothes that do not cover the 'awrat (parts of the body that must be covered) or involve imitation of men; because clothes are not considered tools of oppression, so tailoring them does not fall under cooperation in sin and aggression.

Ibn Taymiyyah distinguished between two types of cooperation: 1. Cooperation in righteousness and piety: This is what Allah and His Messenger have commanded. 2. Cooperation in sin and aggression: This is what Allah and His Messenger have forbidden, such as aiding in the shedding of unlawful blood, or taking unlawful wealth, or striking someone who does not deserve to be struck.

If a Muslim wishes to abstain from this out of scrupulousness, there is no harm in it, provided that no harm befalls him.

It has been narrated from the Salaf (pious predecessors) a warning against entering upon oppressors, or being content with their oppression, or aiding them, or falsely slandering others to them. Indeed, Sufyan al-Thawri and Imam Ahmad considered anyone who sews clothes for them, or sells them needles and threads, or assists them in their personal affairs, to be among the helpers of oppressors or oppressors themselves.