Measurements of $C\!P$ violation in neutral B meson mixing and in the interference with decays are
excellent probes to search for physics beyond the Standard Model.
A selection of recent measurements performed by the LHCb experiment using the full Run I
dataset is presented. These are a measurement of $C\!P$ violation in the B to double charm decay
$B^0\to D^+D^−$, the first measurement of the $C\!P$ violating phase $\phi_s$ using $B_s\to\psi(2S)\phi$ decays, and
a measurement of the $C\!P$-even Bs lifetime in $B_s\to J\!/\!\psi \eta$ decays. Unprecedented flavour tagging
performance is achieved in the $B^0\to D^+D^−$ decay thanks to new flavour tagging methods.