  In this talk, we discuss a simplified version of a recently proposed twin
Pati-Salam (PS) theory of flavour broken to the $G_{4321}$ gauge group at high
energies, then to the Standard Model at low energies, yielding a TeV scale
vector leptoquark $U^{\mu}_1(3,1,2/3)$ which may be used to address the lepton
universality anomalies $R_{K^{(*)}}$ and $R_{D^{(*)}}$ in $B$ decays. The model
also accounts for quark and lepton mass hierarchies, providing a link between
the flavour anomalies and a theory of flavour.
