Williams Coaches said one of its services is facing “significant delays” because of the crash, and the road is expected to be closed for “several hours”.

A spokesperson said: “The A470 is currently closed between Merthyr Tydfil and Brecon due to a serious collision. The road is likely to be closed for several hours. This will cause significant delays to our T4 service. We apologise for any inconvenience this may cause.”