  Aims: We characterised the properties of the bar hosted in lenticular galaxy
NGC 4277, which is located behind the Virgo cluster.
  Methods: We measured the bar length and strength from the surface photometry
obtained from the broad-band imaging of the Sloan Digital Sky Survey and we
derived the bar pattern speed from the stellar kinematics obtained from the
integral-field spectroscopy performed with the Multi Unit Spectroscopic
Explorer at the Very Large Telescope. We also estimated the co-rotation radius
from the circular velocity, which we constrained by correcting the stellar
streaming motions for asymmetric drift, and we finally derived the bar rotation
rate.
  Results: We found that NGC 4277 hosts a short ($R_{bar}=3.2^{+0.9}_{-0.6}$
kpc), weak ($S_{bar}=0.21 \pm 0.02$), and slow ($R=1.8^{+0.5}_ {-0.3}$) bar and
its pattern speed ($\Omega_{bar}=24.7\pm3.4$ km s$^{-1}$ kpc$^{-1}$) is amongst
the best-constrained ones ever obtained with the Tremaine-Weinberg (TW) method
with relative statistical errors of $\sim0.2$.
  Conclusions: NGC 4277 is the first clear-cut case of a galaxy hosting a slow
stellar bar ($R>1.4$ at more than a 1$\sigma$ confidence level) measured with
the model-independent TW method. A possible interaction with the neighbour
galaxy NGC 4273 could have triggered the formation of such a slow bar and/or
the bar could be slowed down due to the dynamical friction with a significant
amount of dark matter within the bar region.
