Public law comprises several interlinking practice areas that concern relationships between people, government and other public bodies. For law firms dealing with smaller private client matters, this could involve challenging the level of care provided to a disabled person by a local authority, or assisting the parents of a child who has been denied the kind of education they believe they are entitled to. Meanwhile, other firms build up practices in the administrative side of public law. This may involve advising local authorities or central government departments on large-scale concerns, such as national infrastructure development (eg, airport expansions), building up expertise along the way in particular fields of activity, including energy, waste disposal or transport.