  The discovery of very slow pulsations (Pspin=5560s) has solved the
long-standing question of the nature of the compact object in the high-mass
X-ray binary 4U 2206+54 but has posed new ones. According to spin evolutionary
models in close binary systems, such slow pulsations require a neutron star
magnetic field strength larger that the quantum critical value, suggesting the
presence of a magnetar. We present the first XMM-Newton observations of 4U
2206+54 and investigate its spin evolution. We find that the observed spin-down
rate agrees with the magnetar scenario. We analyse ISGRI/INTEGRAL observations
of 4U 2206+54 to search for the previously suggested cyclotron resonance
scattering feature at ~30 keV. We do not find a clear indication of the
presence of the line, although certain spectra display shallow dips, not always
at 30 keV. The association of these dips with a cyclotron line is very dubious
because of its apparent transient nature. We also investigate the energy
spectrum of 4U 2206+54 in the energy range 0.3-10 keV with unprecedented detail
and report for the first time the detection of very weak 6.5 keV fluorescence
iron lines. The photoelectric absorption is consistent with the interstellar
value, indicating very small amount of local matter, which would explain the
weakness of the florescence lines. The lack of matter locally to the source may
be the consequence of the relatively large orbital separation of the two
components of the binary. The wind would be too tenuous in the vicinity of the
neutron star.
