The royalists appear to have had warning of the parliamentarian approach and deployed musketeers, one account suggests 200, in the hedgerows at ‘half a mile compass’ about the town. These soldiers surprised the parliamentarian vanguard as it advanced into musket range and a firefight quickly developed in the hedged fields around the town. It was one o’clock in the afternoon.It seems likely that it was the Kingsbridge force that first engaged the royalists on the east or south-east side of the town. If this is correct, the modern Ordnance Survey mapping identifying the location of the battlefield is probably broadly correct, though the area involved may have extended further to the south.

The interaction between the Kingsbridge and Plymouth forces is only vaguely described in the primary sources. The account taken from the earl of Stamford’s letter to the earl of Essex, who was Parliament’s captain-general based at Windsor at this time, suggests the original plan had been to fall on Modbury early in the morning and the Plymouth force had marched overnight to arrive on time. However, it goes on to state ‘that had the other Brigadoes an equall haste in their march, the enemy had clearly been cut off’, suggesting the Kingsbridge force arrived later than expected. The earlier arrival in the vicinity of the town of the Plymouth force, which was insufficient in size to be confident of attacking Modbury successfully, may therefore have been what alerted the royalists and caused them to deploy musketeers into the hedges around the town to cover the main approaches. Alternatively, the Plymouth force’s overnight seizure of Flete House, around 2.7km west of Modbury, as they advance on the town may similarly have raised the alarm.

That Modbury was attacked from two sides appears to be confirmed by one account which suggested that the parliamentarian forces attacking from the east had expected the Plymouth force to have covered the royalist escape from Modbury to the west at the end of the battle and the failure to do so was neglectful. On this basis, it seems likely that the royalists were faced with attacks on their positions around and inside the town from the west, south and east.

The Kingsbridge force, and probably those from Plymouth, fought the royalists from hedge to hedge and forced them back toward the town. With night approaching ‘they [the parliamentarians] drave most of them [the royalists] into the Towne, and to their Workes’. That the royalists were driven into the town and then to their ‘works’ perhaps suggests that the defences had been developed within an area of the town that was more easily defended by the number of men available rather than encompassing the whole of Modbury. If so, the natural area for this would have been around the church and the manor house. This seems to have been where the royalists were eventually forced back into if their reputed eventual escape along Runaway Lane (see below), a short distance from this area to the west, is correct.

Fighting then continued overnight with the parliamentarians making attacks on the royalist works. One account describes parliamentarian artillery firing ‘wild fire’, an incendiary munition, which set alight houses near the royalist defences.

The parliamentarians claimed to have forced the King’s men from their works during this fighting, though royalist accounts indicate that by three in the morning on 22 February their ammunition was running out and they resolved to withdraw from the town, according to local tradition along what is now called Runaway Lane. A screen of sixty dragoons, who had orders to continually fire on the parliamentarians to make it seem the whole royalist army continued to defend the town, covered this escape. Nevertheless, some indiscipline seems to have set in as the parliamentarians reported the capture of around 1,000 arms which had been cast away by the retreating soldiers, suggesting the withdrawal ultimately became a flight, possibly because once the parliamentarians realised what was happening, they chased their fleeing enemy, probably using cavalry from the Plymouth force. In the pursuit the royalists had taken prisoner 70 infantry and 40 cavalry, including four captains and three ensigns. In the town they left five pieces of ordnance, of which two were brass pieces and two were murderers (probably a sub-one pounder breach loading piece of ordnance firing round and case shot) which also fell into parliamentarian hands.

Both sides disputed the number of casualties they had each inflicted. The parliamentarians claimed 100-120 royalists killed, though the royalist Sir Bevill Grenville, who was at Tavistock at the time of the battle, suggested his party had lost only ten slain and a few injured. Grenville also placed the number of parliamentarians killed at 300-500 men, though they claimed only three slain and a small number of prisoners.