The A1308 number is allocated to the former route of the A45 (itself now renumbered A14) through Stowmarket in Suffolk.
The road starts at the dumbbell J49 and heads southeastwards parallel to the A14. For a short distance the two roads are merely a crash barrier apart, before the A1308 bears left to go under the main road and reach a roundabout on the northern edge of Stowmarket, where it turns left. It continues along the same line into town along Bury Road to the next roundabout. This is where it leaves the original line of the A45 to move onto the town centre relief road, Gipping Way. The road remains urban - but is a major improvement on the old line of the road.
Gipping Way, Stowmarket
We continue southeastwards, running in the narrow gap between the River Gipping and the town centre. There is a short multiplex with the B1115 between adjacent sets of traffic lights, after which the road passes a Morrisons supermarket and edge-of-town light industry. The Rattlesden River (a tributary of the Gipping) is then crossed, after which we meet a roundabout and rejoin the old A45. There is a short dualled section as far as the next roundabout, where the road ends at a triple point. The continuation of the ex-A45 ahead is now numbered B1113 whilst the road to the left, back to the A14, is the A1120.
The A1308 was created in the 1970s when the A45 was moved onto the town's bypass. Originally it followed the old route of that road through the town centre but was moved onto Gipping Way when that road opened in 1994, allowing the old road to be pedestrianised.
The original western end of the road was about half a mile further east. The roundabout on the northern edge of Stowmarket mentioned above used to be part of the GSJ at the end of the A1308, with north-facing sliproads splitting from here to meet the A45 (and later the A14); there were no south-facing sliproads. Construction of the Haughley Bends realignment in 2008 rerouted the A14 for a few miles west of here. The northbound onslip was closed off and the A1308 extended over what was the southbound offslip (thus making the road two-way). The point where the two roads are adjacent was the old diverge - and then the A1308 follows the former southbound carriageway past a service station that has remained open to reach the new location of the GSJ, which is now full-access.