The siege of Basing House, notwithstanding an attempt of his younger brother, Lord Charles Paulet, to deliver it up to the enemy, lasted from August 1643 to 16 October 1645, when, during the general decline of the Royal cause, it was taken by storm, after a determined defence, by Oliver Cromwell.

[3] The brutality with which the house was sacked was most unusual, as atrocities against civilians during the Civil War were rare and generally discouraged by both sides: the explanation may be the presence of a number of Catholic priests among the defenders.

[2] The Marquess was made prisoner with such of his garrison as survived the fight; ten pieces of ordnance and much ammunition were also taken by the victors, as Oliver Cromwell himself, who directed the assault, wrote to the Speaker.

Lady Winchester, who had escaped from Basing two days before its fall, was sent to join her husband in the Tower on 31 Jan, and a weekly sum of 10l., afterwards increased to 15l., was ordered to be paid her for the support of herself and her children, with the stipulation that the latter were to be educated as Protestants.

Charles converted to the Church of England, a great blow to the Roman Catholic community of Hampshire, who had for many years looked to the Paulet family to shield them from the worst rigours of the Penal Laws.