  We propose extensions of the anti-$k_t$ and Cambridge/Aachen hierarchical jet
clustering algorithms that are designed to retain the exact jet kinematics of
these algorithms, while providing an infrared-and-collinear-safe definition of
jet flavour at any fixed order in perturbation theory. Central to our approach
is a new technique called Interleaved Flavour Neutralisation (IFN), whereby the
treatment of flavour is integrated with, but distinct from, the kinematic
clustering. IFN allows flavour information to be meaningfully accessed at each
stage of the clustering sequence, which enables a consistent assignment of
flavour both to individual jets and to their substructure. We validate the IFN
approach using a dedicated framework for fixed-order tests of infrared and
collinear safety, which also reveals unanticipated issues in earlier approaches
to flavoured jet clustering. We briefly explore the phenomenological impact of
IFN with anti-$k_t$ jets for benchmark tasks at the Large Hadron Collider.
