According to Trading Standards, it is estimated that more than 106,000 complaints about rogue traders are logged every year. Disreputable companies carrying out substandard work wastes £1.5billion each year, as consumers have to fund the repairs to the damage they cause.
The local authority may serve an enforcement notice on the property owner requiring them to alter or remove work which contravenes the regulations (section 36 of the 1984 Act). If the owner does not comply with the notice the local authority has the power to undertake the work itself and recover the costs of doing so from the owner.
Notwithstanding the possibility of enforcement action, you should also bear in mind that without a completion certificate from building control for notifiable works, the contravention may only come to light when you wish to sell your property. If the work has been done cheaply and without building control involvement, the work will not be registered and therefore a local land search at time of the mortgage application will highlight the omission and the mortgage application refused. You will then have the cost of rectification maybe years after the contractor has gone.