Other Relatives of Peers
So far we have dealt with the sons and grandsons of peers who are in the direct line of heirship and whose courtesy styles are those of peerages. Now we come to the courtesy styles of other relatives.
All younger sons of dukes and marquesses prefix the style Lord to their Christian and surnames, and all daughters similarly use the prefix Lady. Thus we have Lord Eustace Percy, younger son of a Duke of Northumberland, and Lord David Cecil, younger son of a Marquess of Salisbury; Lady Elizabeth Percy, daughter of a Duke of Northumberland, and Lady Gwendolen Cecil, daughter of a Marquess of Salisbury.
In such cases the Christian name can never be omitted. To do so in the case of males would be to infer that they are peers or holders of courtesy peerages. To do so in the case of a female is to infer that she is the wife of any titled person from a marquess to a knight.
All younger sons of an earl have "the Honourable" similarly prefixed to their Christian and surnames, but all daughters use the prefix Lady as in the case of daughters of dukes and marquesses.
All children of viscounts and barons (except for eldest sons in the case of Scots peerages), whether sons or daughters, bear the style "the Honourable" without distinction.
The only grand-daughters of peers entitled to bear courtesy titles are those of dukes, marquesses and earls when they are the offspring of an elder son. In the first two cases, if the son's courtesy style is that of marquess or earl they are called "Lady", but if their father's style is viscount they are usually styled "the Honourable". But the inconsistencies which one comes across on this point have been referred to earlier. In the case of an earl, whether the son's courtesy title is that of a viscount or a baron, his daughters are called "the Honourable".