  The LHCb experiment will operate for about five years at a luminosity of
2x10^32 cm^-2 s^-1 and plans are to accumulate a data sample of ~10 fb^-1. Here
we present the physics programme and detector design for a future high
luminosity phase of the LHCb experiment. An upgraded LHCb experiment would
operate at ten times the design luminosity, i.e. at ~2x10^33 cm^-2 s^-1 and
aims to collect a data sample of ~100 fb^-1 over five years. This programme
would allow the probe of new physics at an unprecedented level. Key
measurements include the B^0_s mixing phase phi_s in B^0_s -> J/\psi phi and
B^0_s -> phi phi decays with a significant sensitivity to the small Standard
Model prediction and a very precise measurement of the CKM angle gamma in tree
diagram decays. Initial studies of the modified LHCb trigger and detectors are
presented. The upgraded LHCb experiment can run with or without an LHC
luminosity upgrade.
