Peter Augustine Baines (1786/87–1843) was an English Benedictine, Titular Bishop of Siga and Vicar Apostolic of the Western District of England.

[2] Bishop Peter Bernardine Collingridge, Vicar Apostolic of the Western District selected Baines as his coadjutor.

The Western District differed from the other three in that the bishop had always been chosen from among the regular clergy, Benedictines or Franciscans, and a large proportion of the missions were in their hands.

Baines thought that he saw the solution of his difficulty in utilising the recently opened Downside School, near Bath, under Benedictine management.

He at once revived his scheme for the seminary at Downside, and, having failed to secure the consent of the monks, he put forward the contention that the monasteries at Downside and Ampleforth had never been canonically erected, for, owing to the unsettled condition of the English mission, the formality of obtaining the written consent of the ordinary had been overlooked.

The case was argued out in Rome, but it was considered that, even if the strict law was on Bishop Baines' side, equity demanded that the rights of the Benedictines should be maintained, and a sanatio was issued by papal authority, making good any possible defects in the past.