The earliest judicial status of an Englishman was that of a subject of the king or queen. The subject was bound to the monarch by the tie of allegiance, and the monarch was reciprocally bound to provide his subjects with protection. It was said in Calvin’s Case (1608) 7 Co Rep 1a:
Ligeance is a true and faithful obedience of the subject due to his Sovereign. - This ligeance and obedience is an incident inseparable to every subject: for as soon as he is born he oweth by birth-right ligeance and obedience to his Sovereign.... [A]s the subject oweth to the King his true and faithful ligeance and obedience, so the Sovereign is to govern and protect his subjects.... Therefore it is truly said that protectio trahit subjectionem, et subjectio protectionem.Blackstone had this to say:
Natural-born subjects are such as are born within the dominions of the crown of England, that is, within the ligeance, or as it is generally called, the allegiance of the king; and aliens, such as are born out of it. Allegiance is the tie, or ligamen, which binds the subject to the king, in return for that protection which the king affords the subject. The thing itself, or substantial part of it, is founded in reason and the nature of government; the name and the form are derived to us from our Gothic ancestors....These notions continued to be echoed in cases as late as the last century. It was said in the famous treason case of R v Casement  1 KB 98:
Natural allegiance is such as is due from all men born within the king's dominions immediately upon their birth. For, immediately upon their birth, they are under the king's protection; at a time too, when (during their infancy) they are incapable of protecting themselves. Natural allegiance is therefore a debt of gratitude; which cannot be forfeited, cancelled, or altered, by any change of time, place, or circumstance, nor by any thing but the united concurrence of the legislature.... For it is a principle of universal law, that the natural-born subject of one prince cannot by any act of his own, no, not by swearing allegiance to another, put off or discharge his natural allegiance to the former: for this natural allegiance was intrinsic, and primitive, and antecedent to the other; and cannot be devested without the concurrent act of that prince to whom it was first due.
[T]he subjects of the King owe him allegiance, and the allegiance follows the person of the subject. He is the King's liege wherever he may be, and he may violate his allegiance in a foreign country just as well as he may violate it in this country.It was said in another famous treason case, Joyce v DPP  AC 347:
Allegiance is owed to their sovereign Lord the King by his natural born subjects; so it is by those who, being aliens, become his subjects by denization or naturalization... so it is by those who, being aliens, reside within the King’s realm. Whether you look to the feudal law for the origin of this conception or find it in the elementary necessities of any political society, it is clear that fundamentally it recognizes the need of the man for protection and of the sovereign lord for service. “Protectio trahit subjectionem et subjectio protectionem.” All who were brought within the King’s protection were ad fidem regis: all owed him allegiance.With the union of England with Scotland in 1706 came the concept of the "British subject". The Union with Scotland Act 1706 refers expressly to "Subjects of the United Kingdom of Great Britain". The concept of a British subject still survives in law - Sir Terry Wogan is one, for example, by virtue of having been born in Ireland when it was still part of the King's realms - but it has become a relatively obscure residual category.
Modern British nationality law dates from the British Nationality Act 1948, which created the concept of the "Citizen of the United Kingdom and Colonies". Lord Justice Lawton summed up this development in R v Secretary of State for the Home Department, ex p Thakrar  QB 684:
The King was under a duty to protect his liege subjects. Until the British Nationality Act 1948, the status of a British subject was based on allegiance. The right to come to the United Kingdom was enjoyed by those who owed allegiance. Those who lived overseas in territories which had been settled as colonies, ceded or acquired by conquest, did owe allegiance; but those who lived in territories which the Crown for various reasons found it convenient to administer without annexation probably did not owe allegiance....
The Act of 1948 swept away the long established concept of allegiance as the basis of British citizenship and replaced it by new concepts.In fact, it is not clear that the 1948 Act did sweep away altogether the concept of allegiance. The concept is still endorsed by (for example) the editors of Halsbury's Laws.
British nationality today
The law of British nationality is currently governed by the British Nationality Act 1981.
In all, there are six different categories of British nationality:
• British Citizen
• British Overseas Territories Citizen
• British Overseas Citizen
• British National (Overseas)
• British Protected Person
• British Subject
EU law also gives rise to the concept of a "national of the United Kingdom". This term refers to:
• British Citizens
• British Subjects who are not subject to UK immigration controls
• British Overseas Territories Citizens who acquire their citizenship from a connection with Gibraltar.
Rights and duties
The following is a summary of the rights and duties of British citizenship. It is taken in part from Lord Goldsmith QC's 2008 report Citizenship: Our Common Bond. At the time, the serious debate over the future of British citizenship which the report sought to contribute to was derailed by the media's decision to focus on the essentially frivolous question of whether schoolkids should be made to swear an American-style oath of allegiance.
Note that many of the following rights and duties also relate to UK residents who are not citizens.
• The right of protection.
• The right of abode, meaning the freedom to enter, leave and reside in the United Kingdom.
• The right to travel inside the UK, within the Common Travel Area and within the European Economic Area.
• The expectation of receiving a British passport.
• The right to British diplomatic protection and consular assistance.
• The right to vote in elections and referendums.
• The right to stand in elections.
• The right to hold public offices governed by the Act of Settlement 1700.
• The rights to donate to a political party and to campaign in a referendum.
• Full rights of access to benefits and services such as healthcare and education.
• The duty of allegiance to the Crown.
• The duty to obey the law.
• The duty to pay taxes and National Insurance contributions.
• The duty to undertake jury service.
• The duty to provide information for the electoral register on request.
• The duty to register births and deaths.
• The duty to notify certain infectious diseases.
• The duty to participate in censuses.
• The duty to "assist the officers of the law, when duly required to do so, in preserving the public peace" (R v Brown (1841) Car & M 314).
Historical duties which have never been repealed
• The duty to serve in the Royal Navy if impressed to do so.
• The duties to serve, if called upon, as a sheriff or parish constable.