On 31 August Cromwell did withdraw; the English army reached Dunbar on 1 September, having taken two days to march the from Musselburgh, harassed day and night by the pursuing Scots. The road was left littered with abandoned equipment and the men arrived hungry and demoralised. The Scottish army outflanked the English, blocking the road to Berwick and England at the easily defended Cockburnspath Defile. Their main force encamped on the Doon Hill, south of Dunbar, where it overlooked the town and the coastal road running south west from the town. The hill was all but invulnerable to direct assault. The English army had lost its freedom of manoeuvre, although they could supply themselves by sea and, if needs be, evacuate the army the same way. On 2 September Cromwell surveyed the situation, and wrote to the governor of Newcastle warning him to prepare for a possible Scottish invasion.