British Steel Ltd.’s three-year run as a company ended May 22, putting 5,000 jobs at risk and piling fresh misery on the U.K.’s manufacturing base.

The company was put into liquidation by the U.K. High Court, which appointed Ernst & Young LLP to manage the process. Despite last-minute pleas for a government rescue and pressure from Labour lawmakers and unions to nationalize the steelmaker, a bailout was ultimately denied.

“We can only act within the law, it is clear that it would be unlawful to provide a guarantee or loan on the terms requested by the company,” said Prime Minister...