Brecon and Radnorshire’s MP and MS have criticised the Liberal Democrats for their decision not to take part in a key vote on the new 20mph speed limit.

On Sunday, Wales became the first country in the UK to reduce speed limits in built-up areas from 30mph to 20mph.

Welsh ministers said the move will reduce deaths and noise, as well as encourage people to walk or cycle for their journeys - although the decision has been met with much opposition.

The law affects 35 per cent of Welsh roads where lamp posts are no more than 200 yards (183m) apart.

Last Wednesday, Lib Dem MS Jane Dodds chose not to vote on a Welsh Conservative motion against the 20mph limit. The motion called on the Welsh Government to scrap the plans.

The Welsh Conservatives expressed support for a 20mph limit around schools, hospitals, and care homes, but called the blanket rollout “disastrous, frankly ludicrous and a war on motorists”.

Ms Dodds did not register a vote on the motion against the plans. Last Wednesday was her birthday and she left the Senedd early that day.

Ms Dodds had previously confirmed her support for the policy. During a Senedd session in June, she cited Public Health Wales predictions that the move will “save an estimated six to 10 lives and between 1,200 and 2,000 casualties every year.”

James Evans MS said: “I was proud to have cast my vote in favour of ordinary working people – against the new 20 mile an hour limit. We expected Plaid and the Labour Party to stand together because that’s what nationalists do. But Jane had the opportunity to take a stand for her constituents and she chose not to. We are elected to Parliament to vote and abstaining shows an unwillingness to take a difficult decision.

“Kirsty Williams failed to cast her vote in favour of Welsh farmers and now Jane has abandoned ordinary working people who will be hardest hit by this change. You can never trust the Liberal Democrats to take a stand on anything.

Fay Jones MP added: “The Liberal Democrats have made it clear that they support the Labour Party in their determination to slow Wales down. The Liberal Democrats have rowed in behind Labour again, totally ignoring the problems that we face in our part of rural Mid Wales.

“Powys County Council – again led by the Liberal Democrats and Labour – has the power to take steps to tackle the problems that we face in Brecon and Radnorshire with noisy motorbikes and excess speeding. But instead, they have meekly followed the Labour Party in their latest attempt to control our lives.”

Although Ms Dodds’ office chose not to respond formally to these comments, it said she had a “long-standing family commitment” which meant she was unavailable during plenary on Wednesday afternoon, which she was unable to reschedule.

It added that Ms Dodds has missed “very few votes” during her time in the Senedd and accused the Conservative opposition as “more posturing than policy”.

Powys County Council Leader Cllr James Gibson-Watt said: “‘I fully support the 20mph policy and it is high time that the Tories stopped misleading people about it. This is not a ‘blanket’ policy as they keep saying - many current 30 mph roads will remain as 30mph ones. 20mph will only apply in residential areas, where there are high concentrations of pedestrians and where 30mph is manifestly too high a speed limit.

“Do the Tories really believe that drivers should be doing 30mph through the narrow streets of our market town centres, villages streets and housing estates? The evidence is clear that this policy will save lives, reduce injuries and improve the quality of the lives of many people across Powys and Wales.”

The speed limit reduction will cost £32.5m.

The Welsh Government said this will be ”outweighed” by reduced impact on the NHS and emergency services, although one of the government’s own documents said longer journeys could cause a “substantial” economic disadvantage.