For great coolness and bravery on the 30th of July, 1857, during the retreat of the British Troops from Arrah, in having climbed, under an incessant fire, outside the Boat in which he and several Soldiers were, up to the rudder, and with considerable difficulty cut through the lashing which secured it to the side of the boat. On the lashing being cut, the boat obeyed the helm, and thus thirty-five European Soldiers escaped certain death.
On 25 July 1857 sepoys mutinied at Dinapur, a large military cantonment on the Ganges about twelve miles west of Patna in Bihar. Driven out of the town and reinforced by the forces of Kunwar Singh, Rajah of Jagdispur, on the 26th they attacked Arrah, more than twenty miles to the west. European women and children had been evacuated from the town in June. Their menfolk, together with a detachment of Sikh policemen, were now besieged in the hastily fortified house of Mr Boyle, a railway engineer. On 29 July Captain Dunbar with a relief force, including some civilian volunteers, left Dinapur by boat and travelled up the Son, a southern tributary of the Ganges, before landing and marching on Arrah. Here on the 30th they were ambushed by the rebels. Dunbar was killed and the force withdrew to their boats under heavy fire. 200 men were killed, and many more wounded. W F McDonell and R L Mangles, both members of the Bengal Civil Service, were awarded the VC for their gallantry in this action after a new Royal Warrant extended the award to Civilians who had fought in the Mutiny. Mangles had saved the life of Private R Taylor of the 37th Regiment. The rescue of Ensign Erskine in the same action by Private D Dempsey VC, 1st Battalion, 10th Regiment, was included in Dempsey’s VC Citation. Arrah itself was not relieved until 2 August 1857.
The grave of McDonnell VC, one of only four civilians awarded the VC was cleaned in January 2023 in St Peter's church Leckhampton. Two other VC memorials, Reynolds VC and Buckley VC were also cleaned at the same time. Fellow civil servant Ross Mangles VC's grave had been cleaned in 2021 by the Trust. A commemorative plaque was presented to the church for public display.