true-blue
From Longman Dictionary of Contemporary EnglishRelated topics: Groupingstrue-blueˌtrue-ˈblue adjective 1 British English informalPPG believing completely in the ideas of the British Conservative Party a true-blue Tory2 American EnglishFAITHFUL completely loyal to a person or idea a true-blue friendExamples from the Corpustrue-blue• However, his opponents are convinced that even in true-blue East Hampshire Tory popularity is on the wane.• The predicted backlash from true-blue supporters has never materialised.