That month, NRW officers collected water samples from the river adjacent to the building site which showed high levels of suspended solids – small solid particles which remain in suspension in water.

Enzo’s Homes pleaded guilty at Cwmbran Magistrates' Court to causing an illegal water discharge activity under Environmental Permitting Regulations.

The firm was fined £20,000, ordered to pay a £2,000 victim surcharge and NRW costs of £7,389.42.

Alastair Krzyzosiak, environment officer for NRW, said: “The construction industry has a duty of care to the communities in which they operate, to ensure the correct controls and safeguards are in place in order to prevent incidents such as these occurring.

“If construction companies plan properly, even during periods of very heavy rain, there should be no ecological impact.

“I hope this fine will send out a clear message that environmental legislation is to be taken seriously.

"We will not hesitate to take appropriate action against those who disregard regulations and jeopardise the natural environment we all know and love.”