  Neutron stars are thought to be born rapidly rotating and then exhibit a
phase of a rotation-powered pulsations as they slow down to 1-10 s periods. The
significant population of millisecond pulsars observed in our Galaxy is
explained by the recycling concept: during an epoch of accretion from a donor
star in a binary system, the neutron star is spun up to millisecond periods.
However, only a few pulsars are observed during this recycling process, with
relatively high rotational frequencies. Here we report the detection of an
X-ray pulsar with $P_{\rm spin} = 1.20$ s in the globular cluster B091D in the
Andromeda galaxy, the slowest pulsar ever found in a globular cluster. This
bright (up-to 30% of the Eddington luminosity) spinning-up pulsar, persistent
over the 12 years of observations, must have started accreting less than 1 Myr
ago and has not yet had time to accelerate to hundreds of Hz. The neutron star
in this unique wide binary with an orbital period $P_{\rm orb} = 30.5$ h in a
12 Gyr old, metal rich star cluster, accretes from a low mass, slightly evolved
post-main sequence companion. We argue that we are witnessing a binary formed
at relatively recent epoch by getting a $\sim 0.8M_\odot$ star in a dynamical
interaction -- a viable scenario in a massive dense globular cluster like B091D
with high global and specific stellar encounter rates. This intensively
accreting non-recycled X-ray pulsar provides therefore a long-sought missing
piece in the standard pulsar recycling picture.
