Waller set off late on 26 October and camped overnight far to the north. His force broke camp and resumed its outflanking move on 27 October while Manchester launched a diversionary attack on Shaw House. Although the Royalists at Donnington Castle observed Waller's movement, and even sent a small detachment of cavalry to harry his rearguard, the troops at Speen were not warned of the danger. Waller's force crossed to the south bank of the Lambourn at Boxford, and formed up and attacked at 3 o'clock in the afternoon, with cavalry under Oliver Cromwell on the left flank, infantry under Philip Skippon in the centre and cavalry under Sir William Balfour on the right.