|To:||Cardiff International Airport (ST066683)|
|Via:||St Brides Major, Llantwit Major|
|Length:||15.9 miles (25.6 km)|
|Meets:||A473, A48, B4524, B4270, A4226|
|Old route now:||A4226, A4050|
|Route outline (key)|
Starting from a traffic-light-controlled junction on Cowbridge Road (the A473, formerly the A48) on the south side of Bridgend, the route first heads southward, crossing By-pass Road (the present A48) at a roundabout and then the Vale of Glamorgan railway line (Bridgend to Cardiff via Llantwit) before leaving the built-up area.
The road gently descends to cross the River Ewenny at the village of the same name. The B4524 (unsigned as such) comes in on the left at the immediate far end of the river bridge before, within 200 m, departing again on the right towards Ogmore by Sea (this time the route number is signed). We will meet this road for a third time later.
Lights control alternate one-way traffic across a narrow railway bridge on St Brides Road as we leave Ewenny. This part of the route is rather narrower and bendier than it appears on the map, running through low wooded hills (which hide extensive limestone quarries) before emerging into Pant St Bride's, a dry valley more representative of "typical" limestone country – one could almost be in Derbyshire! – leading up to the village of St Brides Major. This is where we meet the B4524 again, at the conclusion of its loop down the Ogmore valley and then along the coast through Ogmore by Sea and Southerndown.
From St Brides the B4265 turns to head southeastwards and for the next 9 km parallels the coast, though generally at a distance from the sea of some to 2–3 km so that the main evidence we are near the coast is the sight of seawind-bent trees and hedges. The rich farming landscape traversed here – before and after the village of Wick, which marks the mid-point of this section – lies around 90–100 m above the sea and is level and open, apart from some belts of windbreak trees; the occasional small rises in the road afford long views to the left towards the mountains of the more northerly parts of Glamorgan: a blue smudge on the horizon.
Approaching Llantwit, the road curves to the left and, passing beneath a modern metal-trough railway bridge, begins its northerly bypass of the town and of the adjoining Boverton. This section of the road is a fairly typical single-carriageway modern bypass. It is well hedged and, driving along it, we are little aware, beyond the odd glimpse of rooftops, of the presence of Llantwit or Boverton on our right. Along this section we meet, at a roundabout, the start of the B4270, immediately north of Llantwit town centre, and a rather elaborate signalized junction with a minor road leading to Llanmaes (left) and Llantwit (right). Another railway overbridge of the same type as that met 2.5 km earlier marks the approach to the end of the bypass.
The B4265 continues eastward, still following the general line of the coast but, as before, mostly around 2 km inland – although we do now begin to see flashes of the Bristol Channel to our right. The landscape here is mostly very flat and, appropriately enough, was well populated with airfields during WWII. Earlier we passed close to the former RAF Llandow, site of the 2012 National Eisteddfod of Wales. Now we skirt the southern side of the still very much in-use Ministry of Defence base at St Athan (once claimed to have been the RAF's largest airfield), and our route will take us as far as the northern perimeter fence of Cardiff International Airport (on the site of RAF Rhoose) where it meets up with the A4226 at an end-to-end roundabout junction by the entrance to the airport's aircraft maintenance base.
The B4265 originally started in Llantwit Major - the road west to Bridgend was the B4269 until 1935. East of Llantwit the road follows its original route as far as Burton, to the east of St Athan, after which it originally detoured via East Aberthaw and Port Road. This section was severed by the building of the airport runway hence the current route to the north (although the original detour was to the south along the previously unclassified road through Rhoose).
The B4265 then continued to the north of Barry via Wenvoe to end on the A48 at Culverhouse Cross. The section from Culverhouse Cross to Colcot became the A4050 in 1935 to provide access to Barry. The B4265 was truncated west of this A-road later by the A4226, so that a Class I road reached the airport.