The A483 New Road is blocked after an accident between the B4344 Stone Street (Llandovery) and Irfon Terrace (Llanwrtyd Wells). Police are directing traffic.
The Court of Appeal has rejected Ysgol Pantycelyn Action Group's fight to save the school in Llandovery from closure. They have been fighting since September last year to get Carmarthenshire County Council to reverse its decision to close the school.
The authority is planning to merge the 11 to 19 secondary school with Tregib, near Llandeilo, and to build a new, larger facility on a different site. Lord Justice Maurice Kay today refused the group permission to take their case any further.
The school had argued that the council had "fiddled and fixed" the consultation, but that was rejected by the judge.
But Lord Justice Maurice Kay said it was clear that the action group was able to "have its say" through the consultation into school reform in the county.
The school's closure is part of a £50m project to reorganise secondary education in the area and the plans are currently under consideration by the Welsh Government.