Baron St John of Bletso, in the County of Bedford, is a title in the Peerage of England.

The eldest son of the 1st Earl was advanced to the barony by Writ of acceleration under King Charles I to become the 5th Baron.

However he died in the civil war without becoming Earl, This resulted in the existence of an additional baron in the sequence but this was not taken into account by the family when the barony was continued.

Again according to Round,[1] this was possibly a cadet branch of St John of Basing, Hampshire, and Halnaker, Sussex, which family descended in the male line from the Norman Hugh de Port (d.1091) lord of the manor of Port-en-Bessin in Normandy who took part in the Norman Conquest of England in 1066, and was subsequently granted 53 manors in Hampshire.

However, he predeceased his father (killed at the Battle of Edgehill in 1642) but due to the writ of acceleration issued he is known as the fifth Baron St John of Bletsoe.

He died childless and was succeeded by his younger brother, the third Earl, who represented Bedford in the House of Commons.

The latter's grandson, the fifth Baronet, succeeded as eighth Baron St John of Bletsoe in 1711 (see above for later history of the titles).