A commercial property owner who for years shelled out for drainage bills that it was never obliged to pay must be reimbursed every penny. That was the effect of an important High Court ruling in which utility companies were found to have been unjustly enriched by charging for services that were never provided.

The case concerned premises on an industrial estate. Surface water from the site discharged into a sewer that passed beneath roads on the estate and other land before arriving at an outfall into a brook. The site's owner paid the utility companies for drainage services on the assumption that the sewer was a public facility. It eventually stopped paying, however, and launched proceedings.

Ruling on the case, the Court found that the utility companies had failed to establish on the evidence that the sewer was a public, as opposed to a private, facility. It followed that they were never entitled to charge for the sewer's use and never provided the supposed services for which payment was levied.

The charges had been paid on a mistaken basis and the utility companies had been unjustly enriched by demanding and accepting payment for services to which they were not entitled. It was an aggravating feature of the case that they appeared to have raised charges during a lengthy period when their own records did not indicate that they were entitled to do so. They were ordered to reimburse the owner to the tune of over £150,000, plus interest.