When the contaminated land regime was introduced it was ground-breaking because it imposed potentially unlimited liability on historic polluters with no limit on how far back in time that liability could stretch. The regime places responsibility on the person who has caused or knowingly permitted pollution, whatever their tenure at the time, and whether or not what they were doing at the time was perfectly acceptable or even best practice.

Caselaw on the regime has been scarce. In 2007 the House of Lords held that National Grid were not responsible for the liabilities of British Gas's predecessors where it had acquired part of the British Gas business following privatisation in 1986. In particular, since the contaminated land regime was not in place at the time of privatisation, no liability existed at that time that could be transferred on. In July 2017 the Court of Appeal held similarly that Powys County Council was not responsible for contamination from a landfill site that had been co-owned and operated by predecessor authorities from the early 1960s until 1993, since at the date of succession in 1996 the regime did not exist.

While every case will be determined on its individual facts, the case of Powys illustrates the difficulties with establishing liability under the regime for the historic acts of organisations that have changed in legal personality over time. The Court stressed though that it was not being asked to decide on whether the landowners could enforce under the licence by which the Council's predecessors had occupied the landfill site. This required the licensee not to do anything which could become a "nuisance, damage, annoyance or inconvenience to the Owners…" and was potentially a contingent liability to which Powys could have succeeded in 1996.

This illustrates how the terms of leases and licences may be more significant in securing remediation of sites than statutory regimes like the contaminated land regime. Therefore where there is any risk that a property may suffer from historic or future contamination, it is important to ensure that appropriate environmental liability clauses are drafted into any agreement involving the property.