Despite lacking military experience, Brereton proved an energetic and resolute commander, winning minor victories in March 1643 at Middlewich and Hopton Heath.

In summer 1647, the garrison of Nantwich mutinied; Venables restored order, and was made governor of Liverpool in January 1648, a position he held during the Second English Civil War.

[1] Venables spent the next two years fighting an often brutal counter insurgency war in north Connaught and south-west Ulster; his troops were always in arrears with their pay, and on several occasions he and Jones resorted to confiscating taxes collected for Dublin.

[11] In 1653, he helped implement the Act for the Settlement of Ireland 1652, while resisting attempts to impose Presbyterianism in Ulster; like many in the New Model, he was a religious Independent, who opposed any state-ordered church.

[1] Venables left Ireland in May 1654 and was appointed commander of land forces for the Western Design, an attack on the Spanish West Indies intended to secure a permanent base in the Caribbean.

[12] Planning was based on input from Thomas Gage, a former missionary regarded as an expert on the region who claimed the Spanish colonies of Hispaniola and Cuba were weakly defended, advice which proved incorrect.

[13] Given the distances involved, Venables insisted on flexibility of objectives; Cromwell agreed and his instructions were simply "to gain an interest in that part of the West Indies in possession of the Spaniards".

Leadership was shared with Admiral William Penn, who commanded the fleet, and two civilian commissioners, Edward Winslow, former Governor of Plymouth Colony, and Gregory Butler, who were to supervise colonisation of the captured lands.

[14] Few veterans of the New Model were willing to serve in an area notorious for disease and on an expedition with such vague objectives, so many of the 2,500 troops brought from England were untrained, as well as poorly equipped.

The Spanish had been aware of the project for some time and this additional delay allowed them to send reinforcements to Hispaniola; the plan assumed secrecy and superior English forces, neither of which were true.

Despite opposition from Penn, Venables attacked Jamaica in late May; primarily a resupply point for Spanish ships, the main settlement of Santiago de la Vega was poorly defended and quickly surrendered, although resistance by Jamaican Maroons continued in the interior for several years.

When George Monck took control of Parliament in February 1660, he appointed Venables Governor of Chester, but pressure from local Royalists meant he was removed shortly after the Stuart Restoration in May 1660, ending his public career.