In the early hours of 28 July, the parliamentarians set out along a sandy track from the village of North Scarle, which today is the A156 to Gainsborough. They encountered Cavendish’s advance guard of 100 horse later in the morning, a mile and a half to the south of Gainsborough, in Lea Parish. The parliamentarian advance drove back the royalists, although Colonel Thornhagh was wounded and temporarily captured.

The main body of royalists was positioned at the top of a steep escarpment, known as Foxby Hill, with three regiments of horse in front and the Duke of York’s regiment, commanded by Cavendish, in reserve at the rear. Cavendish had chosen his position well, as he knew that the steepness of the rise from the Lea Road would make it difficult for the parliamentarians to approach.

Meldrum and Cromwell pushed on slowly, with their horses picking their way up the steep hillside covered by rabbit-holes, which formed part of the town’s south warren. They succeeded in gaining the top of Foxby Hill, an extensive plateau area of grassland. Meldrum had organised his force into three ‘brigades’, ascending the hillside in the order of the Lincolnshire troops as a vanguard, Northamptonshire and Nottinghamshire regiments in the centre and Cromwell’s regiment at the rear, in reserve.

The parliamentarians used carbine or musket fire from dragoons, directed upwards at the royalist horse. The royalists’ attempts to impede the parliamentarians’ progress up the hill proved to be ineffective and their forlorn hope was pushed back upon the main body, the line held by the three regiments Cavendish had brought out of Newark.

The vanguard of Lincolnshire troops were the first to reach the top of the hill, followed by the rest of the horse, where they formed into battle array. Cromwell took command of the right wing. The royalist front line advanced upon them, but were counter charged even though the parliamentarians were not fully formed-up. The royalists put up a strong fight, but after some time, the parliamentarians, noticing the royalists were ‘a little shrinking’ in their resolve", pressed them again and caused them to rout. The royalist main body left the field, dividing both to the right and left of Cavendish’s reserve with many of the parliamentarian troops pursuing them for six miles.

Cromwell though had noticed that the royalist reserve commanded by Sir Charles Cavendish was still intact and managed to control three of his cavalry troops.  Cavendish’s men faced Cromwell’s troops for a while before turning to four troops of Lincolners, which also remained on the battlefield, and then charging and routing them. With the rear of Cavendish’s cavalry exposed, Cromwell charged the royalist rear, scattering the Duke of York’s regiment and sending it down the western edge of Foxby Hill, to cross the Summer Gangs and into the marshy meadow ground towards the river. Cavendish and his troops became trapped in this area of ground, described by Cromwell as a “quagmire”. Cavendish was mortally wounded by Captain-Lieutenant James Berry, with a sword-thrust under his short ribs and Lieutenant-Colonel Markham was unhorsed and shot on the ground. Around three hundred royalists in total were killed in the marshy ground. The marsh became known locally thereafter as “Candish bog.”