Sealing a "Culture" in .NET

Hiya folks,

At my job, we need to ensure that our dll runs in a given culture, for example: 
System.Threading.Thread.CurrentThread.CurrentCulture = New Globalization.CultureInfo("en-GB")

Is there any way that we can "seal" the culture in the derived class so that it's hidden, but definitely read-only, and default?
We don't want any derived classes to be able to override it.

Many thanks,
Yogi