Here’s a little bit of nonsense based on something I knocked out to answer a question on the Hidden Northumberland Facebook page to try to clear up the many misunderstandings about Berwick, Tweedmouth and their place in the larger administrative picture.
Tweedmouth (of which Spittal was a part for this purpose) was a parish in the hundred of Islandshire. This had been part of Co Durham, as had Norhamshire until the introduction of the Counties (Detached Parts) Act 1844 when they became hundreds within Northumberland.
The medieval administrative notion of “hundreds” (vaguely defined as an area containing 100 homesteads) was done away with by the Local Government Act of 1894 which introduced urban and rural districts. The two hundreds were merged to form Norham and Islandshire Rural District.
Norhamshire and Islandshire
Meanwhile, north of the river, Berwick had been granted County Corporate status under the Treaty of Norham (1551). The Local Government Act 1888, made County Boroughs of many administrative towns including Counties Corporate, but Counties Corporate continued to “enjoy” the same status they had held before the Act. Thus Berwick was known as the County and Town of Berwick-upon-Tweed until it became the modern Borough and merged with Norham and Islandshire, Belford and Glendale in 1974 and finally became part of Northumberland!