b'Metropolitan Borough Council (1992) ICR 639. In Allsop for example, Lord Templeman stressed that a power is not incidental merely because it is convenient or desirable or profitable. Two more cases (R (on the application of Attfield) v London Borough of Barnet [2013] EWHC 2089 (Admin) and Hemming and others v Westminster City Council [2016] EUECJ C-316/15 that are discussed in more detail in the relevant chapters of Part B have shown that the courts interpretation of charging legislation does not appear to have become any more generous and highlight that charging remains a difficult and sensitive issue. Public law and vires 2.3 As outlined above, identifying a power to undertake a particular activity is only part of the task. To act intra vires an authority must exercise those powers in a lawful manner in accordance with well enshrined public law principles. Consequently, even though some local authorities (as defined under the 2011 Act) will now be able to more easily point to an enabling power (the general powers of competence), they still have to exercise the general competence power itself in accordance with any limitations or prohibitions contained within the 2011 Act and taking account of limitations and prohibitions contained in pre-existing legislation or indeed future legislation (which specifically refers to or limits the general competence powers). The courts have a number of options available at their disposal to prevent abuses of power. For example, the courts can act to prevent a local authority acting illegally, irrationally or with procedural impropriety, Lord Diplock in Council of Civil Service Unions v Minister for the Civil Service [1985] AC 374. Illegality encompasses the decision-maker failing to correctly understand the law regulating the decision-making power and to give effect to it. Irrationality is a decision so outrageous in its defiance of logic that no sensible person having applied their mind to the question to be decided could have arrived at it (also known as Wednesbury unreasonableness). Procedural impropriety includes failure to observe basic rules of natural justice, failure to act with procedural fairness and failure to observe statutory procedural rules. The Wednesbury principles (derived from the case of Associated Provincial Picture Houses Ltd v Wednesbury Corporation [1948] 1 KB 223 are often cited to check abuses of power by authorities. These principles require that in reaching a decision a local authority must: (1)direct itself properly in law; (2)take account of all relevant matters; (3)leave out of account all irrelevant matters; and (4)not come to a decision which no reasonable authority could reach. Backhouse v Lambeth LBC (1972) 116 Sol Jo 802 is but one example of a local authority reaching an irrational decision on the issue of the imposition of charges. Lambeth Council wanted 38'