The erection of parking restriction signs by a local authority, even if found to be an unlawful exercise of power, does not without more give rise to liability in nuisance, misfeasance in public office, negligence, or interference with business by unlawful means. For misfeasance in public office, malice or intention to cause harm must be the actuating motive — acting ultra vires alone is insufficient. The installation and enforcement of parking signs are policy matters to which the tort of negligence does not apply.
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