In this study, we examine how mobility and on-going changes in sociocultural contexts impact family language policy (FLP) in the UK. Using a questionnaire and involving 470 transnational families across the UK, our study provides a descriptive analysis of different family language practices in England and establishes how attitudes influence the different types of FLP in these families. Complementing the descriptive analysis, we use interview data to understand the driving forces behind the different types of language practices and language management activities, and explore how ideological constructs of 'pride', 'prejudice' and 'pragmatism' are directly related to negative or positive attitudes towards the development of children's heritage language. The findings indicate that migration trajectories, social values, raciolinguistic policing in schools, and linguistic loyalty have shaped family decisions about what languages to keep and what languages to let go. Our paper responds to the linguistic and demographic changes in British society, and makes an important contribution to our knowledge about multilingual development of children in transnational families. Critically, this study shows that FLPs alone cannot save the minority languages; institutionally sanctioned language practices and ideologies have to make a move from limiting the use of these languages in educational contexts to legitimising them as what they are: linguistic resources and languages of pride.