The deputy first minister told the Senedd he is optimistic that revenue generated by UK-led reforms to water pollution regulations will stay in Wales.

Huw Irranca-Davies, who is also climate change secretary, appeared before a Senedd committee for scrutiny on Westminster's water (special measures) bill on October 16.

Pressed by the Conservatives’ Janet Finch-Saunders about funds from pollution fines going to the UK Treasury, he said the Welsh Government wants revenue to stay in Wales.

Mr Irranca-Davies told the committee: “That’s the nature of the engagement we currently have with the UK Government. It’s probably fair to say those discussions are going well.”

Plaid Cymru’s Delyth Jewell raised Natural Resources Wales’ evidence on cost recovery, saying fines resulting from prosecution would return to the UK Treasury.

“We’re very cognisant of that …,” the minister replied. “We’re in discussions with the UK Government on exactly that point – making sure the funds … would actually be returned.”

He was optimistic as he pointed to progress on clawing back other funds under the bill.

Llŷr Gruffydd, who chairs the climate change committee, asked whether the bill is in line with Welsh Government policies.

Mr Irranca-Davies said the bill is aligned and builds on progress, providing an opportunity to collaborate on a UK basis as rivers “don’t respect national boundaries”.

He recognised the need to make sure the measures fit Welsh Water’s not-for-profit model.

Calling for automatic penalties, Ms Finch-Saunders warned it takes “so long” to get Welsh Water and NRW to respond to pollution incidents.

The Tory asked: “Do you actually believe we’ve got the right enforcement procedure?”

Mr Irranca-Davies said Welsh ministers fully support proposals for automatic penalties for certain offences which will be set out in secondary legislation in the Senedd.

He said the bill would modify the required standard of proof from beyond reasonable doubt to the balance of probabilities.