In the UK it is the Department for Transport. (DfT)
the FERC
the government agency is accused of unfairly favoring the private interests that it regulates.
fcc
The industry an agency regulates controls the agency that is supposed to regulate it.
The Army Corps of Engineers
The Federal Communications Commission regulates telephone services.
the EPA.
FDA
SEC
FCC
The Federal Trade Commission
Federal Motor Carrier Safety Administration. It's under the United States Department of Transportation.