  We propose that the electroweak and flavour quantum numbers of the Standard
Model (SM) could be unified at high energies in an $SU(4)\times Sp(6)_L \times
Sp(6)_R$ anomaly-free gauge model. All the SM fermions are packaged into two
fundamental fields, $\Psi_L \sim (\mathbf{4}, \mathbf{6}, \mathbf{1})$ and
$\Psi_R\sim (\mathbf{4}, \mathbf{1},\mathbf{6})$, thereby explaining the origin
of three families of fermions. The SM Higgs, being electroweakly charged,
necessarily becomes charged also under flavour when embedded in the UV model.
It is therefore natural for its vacuum expectation value to couple only to the
third family. The other components of the UV Higgs fields are presumed heavy.
Extra scalars are needed to break this symmetry down to the SM, which can
proceed via `flavour-deconstructed' gauge groups; for instance, we propose a
pattern $Sp(6)_L \to \prod_{i=1}^3 SU(2)_{L,i} \to SU(2)_L$ for the left-handed
factor. When the heavy Higgs components are integrated out, realistic quark
Yukawa couplings with in-built hierarchies are naturally generated without any
further ingredients, if we assume the various symmetry breaking scalars
condense at different scales. The CKM matrix that we compute is not a generic
unitary matrix, but it can precisely fit the observed values.
