The 1972 Local Government Act, which came into force on 1st April 1974, put Yarm in a newly created County of Cleveland, under the administration of Cleveland County Council and the Borough of Stockton on Tees. It abolished North Riding County Council, under which Yarm had previously been administered, but it did not abolish the North Riding of Yorkshire. Government statements at the time and since confirm that the "changes were for local government purposes only. For all other purposes Yorkshire is still Yorkshire."
The 1992 Local Government Act, which came into force on 1st April 1996, abolished both Cleveland County Council and the County of Cleveland. It created a new Unitary Council of Stockton on Tees, which included Yarm. But in addition to that new "Ceremonial" Counties were created which legally put Yarm in North Yorkshire for all cultural and ceremonial purposes.
This should be perfectly clear to people and there should be no question at all about Yarm being well and truly part of Yorkshire but there are two problems which muddy the waters and create confusion.
One is the Labour Councillors and activists who see being part of Yorkshire as handing control to "Tory North Yorkshire." They refuse to see it simply as a question of geography - Yorkshire is from the River Tees to the River Humber, from the Pennines to the sea.
The other is the local media who have their readership catchment area that crosses the Tees so they look for a name that lumps us all together and Teesside fits the bill. It is so easy to turn it into a is it Yorkshire is it Teesside debate. The difference is Teesside is not a county Yorkshire is, end of argument.
Yarm's referendum result can be the catalyst for the powers that be alongside the River Tees to accept that south of the Tees we are part of Yorkshire for all cultural, ceremonial and sporting purposes.
It is perfectly legal and proper for the residents of Yarm, indeed all those living immediately south of the Tees, to use Yorkshire as part of their postal address; Councils can erect Yorkshire/Durham boundary signs on the bridges that cross the Tees; and mapmakers can include traditional county boundaries on maps along with local government areas and celebrate Yorkshire Day on 1st August. That is how you show your pride in Yorkshire. It is not about who controls the Council.