The skirmish that took place at Isle Moor on the day before the Battle of Langport played an important part in weakening both the Royalists’ forces and their morale. A sizeable force of horse under General George Porter was taken by surprise and routed near Isle Abbots. Porter, who seems to have had something of a reputation for cowardice, had to be forcibly restrained by Goring himself from fleeing completely with the scattered remnants of his troops.
The following extract is from one of the standard works on the Battle of Langport – The Battle of Langport: a short historical account, by Graham Edwards (1995) p.9-10:
“The fight at Isle Moors.
In the afternoon [of Wednesday 9th July 1645], hearing of a Royalist force at Isle Abbots, Massey divided his force and approached the area from two sides. He surprised George Porter’s Royalist force, catching them quite unprepared, horses unsaddled and some men taking their ease in the meadows. The Royalists were completely routed and were pursued from Isle Moors almost to Langport itself. …This disaster had important repercussions. Goring now realised that he had a strong enemy force at his rear west of the River Parrett, threatening encirclement and also his withdrawal route to Bridgwater. The morale of his cavalry was now at an even lower ebb than before.”
A colourful account of the skirmish can be found in David Underdown’s Somerset in the civil war and interregnum (1973) p.102:
“Goring’s strategy had collapsed, and his tactics now betrayed his desperation. On the morning of Tuesday the 8th he sent his bibulous brother-in-law, Lt-Gen Charles Porter, with most of the cavalry to make a thrust towards Taunton. Fairfax immediately sent Massey’s brigade in pursuit. Some time the next day Porter’s men were relaxing in the meadows of Isle Moor, some asleep, others bathing in the River Isle or strolling along its banks. The officers, as usual, were drinking, and no scouts had been sent out. The peaceful summer scene was ruined by the sudden arrival of Massey’s force, who rounded up 500 startled prisoners and pursued the demoralised remnants across the moors. Goring brought new forces out of Langport to help them, but although he got some of the survivors across the Parrett to safety, he himself was slightly wounded and angrily blamed Porter for his negligence. The entire cavalry, Goring admitted, was ‘very much shattered with the disorder that day’.”