[7] As the political struggle with Charles I intensified, in March 1642 Parliament nominated the devout Puritan Robert Rich, 2nd Earl of Warwick, as commander of the navy, with Batten as his vice admiral and second-in-command.

[7] As later noted by Royalist statesman and historian Edward Hyde, 1st Earl of Clarendon, Batten's prompt action in securing the fleet was a major boost to the Parliamentarian cause.

Its possession allowed them to protect their own trade routes and block Royalist imports, while other countries were wary of antagonising one of the strongest navies in Europe by supporting their opponents.

This gave them control of access to internal waterways, the primary method of moving large bodies of men and supplies until the advent of railways in the 19th century, and prevented Royalist areas in Wales, South-West and North-East England from supporting each other.

In early 1642, Charles had sent his wife, Henrietta Maria, to Europe to purchase weapons; the absence of a secure port delayed her return until February 1643, and even then, she reached Scarborough only after narrowly escaping a squadron led by Batten.

[9] Although the Royalists captured Bristol and Exeter in 1643, they lacked a significant fleet and so Batten spent most of the war resupplying Parliamentarian garrisons or supporting coastal operations.

Batten took over as commander but since his promotion was viewed as temporary, he retained his original rank, a perceived lack of appreciation that marked the beginning of his alienation from the Parliamentarian cause.

Charles surrendered to the Scots in June 1646, but victory highlighted divisions between religious Independents like Oliver Cromwell who dominated the New Model Army, and moderate Presbyterians such as Northumberland and Batten who formed a majority in Parliament.

In June 1647, the army demanded the impeachment of eleven MPs identified as their principal opponents; to escape arrest, they fled by sea to the Dutch Republic in August and were intercepted by Batten, who released them and was removed from command as a result.