Motorists across Wales could face fines of up to £150 for unnecessarily leaving their engines running under new Welsh Government regulations.

With colder mornings approaching, drivers are also being warned against leaving vehicles unattended while defrosting windscreens, potentially risking fines, theft and invalidated insurance claims.

Since 30 September, Welsh councils have been able to issue fixed penalties ranging from £75 to £150 for stationary engine idling, replacing the previous £20 fine.

The penalties can be imposed when motorists unnecessarily leave engines running on public roads and refuse an authorised officer's request to switch them off. Prosecution can result in fines of up to £1,000.

However, the Welsh Government has clarified that running an engine when necessary to safely de-ice or demist windows before a journey is acceptable.

Leaving a vehicle unattended with its engine running on a road remains prohibited, while insurers may refuse claims if a car is stolen after being left running with its keys inside.

Dawn Yates, from Ex felon assistance, warned that drivers frequently leave their vehicles running while returning indoors during frosty mornings.

Drivers are also reminded that the Highway Code requires all windows to be cleared of ice and snow before setting off.

Number plates and lights must remain clean and visible, while improperly using fog lights or driving with insufficient tyre tread can also result in penalties.

Ms Yates added: Dawn added: "Most of these fines are avoidable with five minutes' preparation. Set the alarm a little earlier, keep a scraper and de-icer in the house rather than in the frozen car, and give the plates and lights a wipe when you clear the windows. It's cheaper than any fine, and a lot cheaper than losing the car."

The Welsh Government says the increased idling fines are intended to tackle air pollution, particularly around schools and healthcare facilities.