The answer is: The hostages were freed in 1981 after Reagan’s inauguration.
The hostage crisis when 52 of the united states diplomat were detained by Muslim Student Followers of the Imam's Line.
As soon as Reagan elected, he start a negotiation with Iranian embassy to solve the issue without any military confrontation. As an effort to shows goodwill to the new president, Iranian government freed the hostage after Reagan's inauguration.
The European nations supported the colonists instead of the British because they were enemies of Britain themselves. They believed and agreed that Britain was becoming too powerful.
