For example, the Duke of Norfolk is also the Earl of Arundel and the Lord Maltravers. His eldest son is therefore styled Earl of Arundel. Lord Arundel's eldest son (should he sire one during his father's lifetime) will be styled Lord Maltravers. However, only the Duke of Norfolk is actually a peer; his son Lord Arundel and his hypothetical grandson Lord Maltravers remain commoners.
Courtesy peerages are only used by the peer's eldest living son, and the eldest son's eldest living son, and so forth. Other descendants are not permitted to use the peer's subsidiary titles. Only the Heir Apparent (and Heir Apparent to the Heir Apparent and so on) can use the titles. An Heir Presumptive (e.g. a brother, nephew, or cousin) does not use a courtesy title. However, Scottish practice allows the style Master/Mistress of X to an heir presumptive as well as to an heir apparent; for example, the brother of the present Marquess of Tweeddale has the title Master of Tweeddale.
The wives of courtesy peers are also entitled to courtesy titles, which are the female equivalents of their husbands' titles. Thus, the wife of Earl of Arundel is styled Countess of Arundel.
For the British peerage, written references to holders of courtesy peerages are supposed to be in the form "Marquess of Blandford", "Earl of Arundel", etc., i.e. without the preceding definite article ("The"); substantive peers are named with the article, e.g. "The Marquess of Winchester", "The Earl of Derby".
Titles with the same name as a peer's main title are also not used as courtesy titles. For instance, the Duke of Westminster is also the Marquess of Westminster and the Earl Grosvenor (amongst other titles). The Duke's eldest son is not styled Marquess of Westminster (which would cause confusion between the son and the father), and so is styled Earl Grosvenor instead. The title used does not have to be exactly equivalent to the actual peerage: the eldest son of the current Duke of Wellington is styled Marquess of Douro, even though the actual peerage possessed by his father is Marquess Douro.
If a peer of the rank of Earl or above does not have any subsidiary titles of a name different from his main title, his eldest son usually uses an invented courtesy title of "Lord Surname". For instance, the eldest son of the Earl of Devon is styled Lord Courtenay, even though the Earl has no barony of that name, and similarly the eldest son of the Earl of Guilford is styled Lord North. The eldest son of the Earl of Huntingdon, who has no subsidiary titles, is styled Viscount Hastings to avoid confusion with the substantive peer Lord Hastings. The Earl Castle Stewart's heir uses the style Viscount Stewart in order to avoid confusion with the Lord Stewart, eldest son of the Viscount Castlereagh, eldest son of the Marquess of Londonderry. The Earl and the Marquess are both scions of the House of Stewart.
The daughter of a duke, marquess, or earl who marries a commoner becomes "Lady first name husband's last name". The daughter of a viscount or baron who marries a commoner becomes "The Honourable Mrs husband's last name". If she marries a peer, she gains the courtesy title as that peer's wife.
If a woman marries an Honourable, and holds no higher title, she will become "The Honourable Mrs husband's first name husband's last name." If a woman marries a Lord, she will become "Lady husband's first name husband's last name." In case of a divorce, she will keep the same style as during her marriage, or she may choose to assume the style "Mrs. first name husband's last name." Regardless of what she chooses, she loses all precedence she attained from marriage. Because of the former option, there can be multiple Lady John Smiths.
Until 2004 adopted children of peers had no right to any courtesy title. However as a result of a Royal Warrant dated 30 April 2004 adopted children are now automatically entitled to such styles and courtesy titles as their siblings. However, as with illegitimate children where legitimated, such children have no rights to inheritance of peerages. [Note - Scottish peerages rules of descent differ.]
|Peer||Wife||Eldest Son||Younger Son||Unmarried Daughter|
|Duke||Duchess||Father's Subsidiary Title||Lord Firstname Lastname||The Lady Firstname Lastname|
|Marquess||Marchioness||Father's Subsidiary Title||Lord Firstname Lastname||The Lady Firstname Lastname|
|Earl||Countess||Father's Subsidiary Title||The Honourable Firstname Lastname||The Lady Firstname Lastname|
|Viscount||Viscountess||The Honourable Firstname Lastname||The Honourable Firstname Lastname||The Honourable Firstname Lastname|
|Baron||Baroness||The Honourable Firstname Lastname||The Honourable Firstname Lastname||The Honourable Firstname Lastname|
Occasionally a peer has inherited the title upon the death of a relative who is not one of his parents. (Some say it is incorrect in this case to say the title is inherited from the relative, merely on the death of the relative — since when a peer has no direct descendants, the peerage moves to the second heir of the previous holder (or his heirs), failing that to the second heir of the holder before that (or his heirs), and so in a recursive fashion). When this happens, the relatives in the direct line to the new peer may be allowed to use courtesy titles appropriate to their relationship to that peer or prior heirs. For instance, Rupert Charles Ponsonby, 7th Baron de Mauley inherited the Barony of de Mauley from his uncle in 2002. His brother Ashley had no title, as their father was only an Honourable and was never actually Baron de Mauley. However, in 2003, Ashley was granted by Warrant of Precedence from Queen Elizabeth II the style and precedence that would have been his had his father survived to inherit the barony, becoming The Honourable Ashley Ponsonby. Precedence in such circumstances is usually granted but is not automatic.
The wives of courtesy peers hold their titles on the same basis as their husbands, i.e. by courtesy. Thus the wife of Marquess Douro is known as Marchioness Douro.
In contrast, the wife of a substantive peer is legally entitled to the privileges of peerage: she is said to have a "life estate" in her husband's dignity. Thus a duke's wife is titled a "duchess", a marquess's wife a "marchioness", an earl's wife a "countess", a viscount's wife a "viscountess" and a baron's wife a "baroness". Despite being referred to as a "peeress", she is not a peer "in her own right": this is a 'style' and not a substantive title. However, this is considered a legal title, unlike the social titles of a peer's children.
It is also possible for a woman to be a substantive peer in her own right, by succession or by first creation (i.e. ennoblement, most commonly in recent times under the Life Peerages Act 1958). Her children use courtesy titles according to her rank, as with the children of male peers, but her husband receives no special distinction. Thus the husband of Baroness Bottomley of Nettlestone is called Peter Bottomley and has no courtesy title.
A peeress loses her legal right to the peerage style following divorce. A convention has developed whereby her Christian name is added in front of her former title to distinguish her from subsequent wives of her husband. Hence, "Her Grace The Duchess of London" becomes "Mary, Duchess of London". She is not entitled to the use of the address "Your Grace" (now virtually obsolete) but again by convention, she may be addressed as "Duchess" or "Your Grace". "The Rt Hon. The Lady London" becomes "Mary, Lady London" and may be addressed as "Lady London," or "My Lady".
A divorced peeress's right to the title and dignities of peerage does not end if she subsequently marries a commoner. She may retain the title by courtesy.
It is customary for women with higher titles from one marriage to retain them even on subsequent remarriage. As Lord Macnaughten put it in the case of Earl Cowley v Countess Cowley  AC 450: "...everybody knows that it is a very common practice for peeresses (not being peeresses in their own right) after marrying commoners to retain the title lost by such marriage. It is not a matter of right. It is merely a matter of courtesy, and allowed by the usages of society." The divorce court, in the above case, granted the earl an injunction preventing his wife from using his title; however this was overturned by the Court of Appeal, whose decision was confirmed by the House of Lords, on the grounds that ordinary courts of law lacked any jurisdiction in matters of honour.
The same practice was followed by widows who remarried. A prominent example was Catherine Parr, the last wife of Henry VIII, who continued to be known as Queen even after her marriage to Lord Seymour of Sudeley (and, indeed, she disputed precedence with the wife of her brother-in-law the Duke of Somerset on this basis).
This usage died out later in the twentieth century, and women who remarry now ordinarily take a new married name and do not retain their former title. However, they may choose to continue use of the courtesy title per Cowley v. Cowley.
If a peer dies, his wife's style does not change unless the new peer is married or if the heir is a woman too. If he is married, traditionally the widowed peeress puts "Dowager" in her style, i.e. "The Most Hon. The Marchioness of London" becomes "The Most Hon. The Dowager Marchioness of London."
If a widowed peeress's son predeceases her, her daughter-in-law may not use the title of Dowager and must be styled, e.g. "The Most Hon. Mary, Marchioness of London", until her mother-in-law dies, at which point she may use the title of Dowager. In more recent times, due to negative connotations of the word "Dowager," some widows choose to be styled with their Christian names, instead of as Dowager.
If a peer or knight enters into a civil partnership, his or her partner is not entitled to a courtesy title.
The courtesy titles of children of peers are social, not legal. For this reason, in official documents, Lord John Smith is often referred to as John Smith, Esq., commonly called Lord John Smith; The Hon. Mrs. Smith would be called Mary Jane, Mrs. Smith, commonly called The Hon. Mary Jane Smith. However, there is legal precedence that results from being the wife or child of a peer, even though the styles of the latter are merely social. The wives of peers are peeresses and rank exactly the same as peeresses in their own right.
Children of peers can outrank certain actual peers. For instance, the daughter of a Duke outranks a Countess. However, if the daughter of a Duke marries an Earl, she actually drops to the rank of Countess. But, if that same daughter marries a commoner, she retains her rank. If that daughter marries the eldest son of an Earl, though he may be a courtesy peer, she may keep her rank until the son inherits the Earldom, when she must drop to the rank of Countess.