Question: What court case used the latin phrase Fiat justitia ruat caelum to declare chattel slavery was unsupported by common law in England and Wales?

Context paragraphs:
Somerset v Stewart: Somerset v Stewart (1772) 98 ER 499 (aka "Somersett's case", or in State Trials v.XX "Sommersett v Steuart") is a famous judgment of the English Court of King's Bench in 1772, which held that chattel slavery was unsupported by the common law in England and Wales, although the position elsewhere in the British Empire was left ambiguous.  Lord Mansfield decided that:

Let there be light: "Let there be light" is an English translation of the Hebrew ("yehi 'or") found in of the Torah, the first part of the Hebrew Bible.  In Old Testament translations of the phrase, translations include the Greek phrase γενηθήτω φῶς ("genēthētō phōs") and the Latin phrase fiat lux .

Federal common law: Federal common law is a term of United States law used to describe common law that is developed by the federal courts, instead of by the courts of the various states.  The United States is the only country to combine the creation of common law doctrines with a complete federalism, wherein the national supreme court has virtually no power to review state court decisions to determine whether the state courts have followed state laws.  The High Court of Australia is sometimes said to have federal common law, but because all state and territorial courts are directly appealable to the High Court, this is indistinguishable from a general common law.  In contrast, the United States Supreme Court has effectively barred the creation of federal common law in areas traditionally under the authority of state courts.  Nevertheless, there are several areas where federal common law continues to govern.

Distress damage feasant: Distress damage feasant is a common law self-help legal remedy whereby a person who is in possession of land may impound a chattel which is wrongfully on that land to secure the payment of compensation for damage caused by it.  It is part of the law relating to distraint.  In some cases the party also has the right to sell the chattel.  The chattel may be inanimate, or it may be an animal or livestock.

Common law: Common law (also known as judicial precedent or judge-made law or case law) is the body of law developed by judges, courts, and similar tribunals.  The defining characteristic of “common law” is that it arises as precedent.  In cases where the parties disagree on what the law is, a common law court looks to past precedential decisions of relevant courts, and synthesizes the principles of those past cases as applicable to the current facts.  If a similar dispute has been resolved in the past, the court is usually bound to follow the reasoning used in the prior decision (a principle known as "stare decisis").  If, however, the court finds that the current dispute is fundamentally distinct from all previous cases (called a "matter of first impression"), and legislative statutes are either silent or ambiguous on the question, judges have the authority and duty to resolve the issue (one party or the other has to win, and on disagreements of law, judges make that decision).  The court states an opinion that gives reasons for the decision, and those reasons agglomerate with past decisions as precedent to bind future judges and litigants.  Common law, as the body of law made by judges, stands in contrast to and on equal footing with statutes which are adopted through the legislative process, and regulations which are promulgated by the executive branch (the interactions are explained later in this article). " Stare decisis", the principle that cases should be decided according to consistent principled rules so that similar facts will yield similar results, lies at the heart of all common law systems.

Court of Chancery: The Court of Chancery was a court of equity in England and Wales that followed a set of loose rules to avoid the slow pace of change and possible harshness (or "inequity") of the common law.  The Chancery had jurisdiction over all matters of equity, including trusts, land law, the administration of the estates of lunatics and the guardianship of infants.  Its initial role was somewhat different, however; as an extension of the Lord Chancellor's role as Keeper of the King's Conscience, the Court was an administrative body primarily concerned with conscientious law.  Thus the Court of Chancery had a far greater remit than the common law courts, whose decisions it had the jurisdiction to overrule for much of its existence, and was far more flexible.  Until the 19th century, the Court of Chancery could apply a far wider range of remedies than the common law courts, such as specific performance and injunctions, and also had some power to grant damages in special circumstances.  With the shift of the Exchequer of Pleas towards a common law court and loss of its equitable jurisdiction by the Administration of Justice Act 1841, the Chancery became the only national equitable body in the English legal system.

Slavery: Slavery is, in the strictest sense of the term, any system in which principles of property law are applied to people, allowing individuals to own, buy and sell other individuals, as a "de jure" form of property.  A slave is unable to withdraw unilaterally from such an arrangement and works without remuneration.  Many scholars now use the term chattel slavery to refer to this specific sense of legalised, "de jure" slavery.  In a broader sense, however, the word slavery may also refer to any situation in which an individual is "de facto" forced to work against their own will.  Scholars also use the more generic terms such as unfree labour or forced labour to refer to such situations.  However, and especially under slavery in broader senses of the word, slaves may have some rights and protections according to laws or customs.

Fiat justitia: Fiat justitia is a Latin phrase, meaning "Let justice be done".  Historically in England, a warrant for a writ of error in Parliament or later a petition of right in the courts could be brought only after the king, or on his behalf the Home Secretary, had endorsed "fiat justitia" on a petition for such a warrant.  It was a means of granting leave to appeal by exercise of the royal prerogative.

Fiat iustitia, et pereat mundus: "Fiat justitia, et pereat mundus" is a Latin phrase, meaning "Let justice be done, though the world perish".

Fiat justitia ruat caelum: Fiat justitia ruat cælum is a Latin legal phrase, meaning ""Let justice be done though the heavens fall.""  The maxim signifies the belief that justice must be realized regardless of consequences.  According to the 19th-century abolitionist politician Charles Sumner, it does not come from any classical source.  It has also been ascribed to Lucius Calpurnius Piso Caesoninus, see .  It was used in the landmark judgment, "Somerset v Stewart", where slavery was held to be unlawful at common law.

Supporting paragraphs: Fiat justitia ruat caelum Somerset v Stewart
Answer: Somerset v Stewart