  We present a new model of giant planet formation that extends the
core-accretion model of Pollack etal (1996) to include migration, disc
evolution and gap formation. We show that taking into account these effects can
lead to a much more rapid formation of giant planets, making it compatible with
the typical disc lifetimes inferred from observations of young circumstellar
discs. This speed up is due to the fact that migration prevents the severe
depletion of the feeding zone as observed in in situ calculations. Hence, the
growing planet is never isolated and it can reach cross-over mass on a much
shorter timescale. To illustrate the range of planets that can form in our
model, we describe a set of simulations in which we have varied some of the
initial parameters and compare the final masses and semi-major axes with those
inferred from observed extra-solar planets.
