The recently built X-ray Free Electron Lasers (FEL), the so-called fourth generation light sources, provide extremely intense coherent femtosecond pulses of energetic radiation. These FELs based on Linear Accelerator (Linac) technology require radio-protected facilities which are several kilometres in length and also require significant investment (more than a hundred million euros). They have already produced an impressive list of outstanding results in many scientific fields. As a consequence of these successes they are already significantly over-subscribed by the scientific community. The recent progress realized by laser plasma accelerators that can nowadays deliver high quality energetic particle beams in ultra short bunches (of a few femtoseconds) with very high peak currents (of a few kA) are very encouraging for the future. Thanks to the huge longitudinal electric fields they can produce, laser plasma accelerators appear to be a natural candidate to reduce the size and cost of future FELs. Among the many applications laser plasma accelerators sustain, the hope to build a compact Free Electron Laser, has been clearly identified by the scientific community as the near future grand challenge. The goal of the X-five project is then to demonstrate the feasibility of such fifth generation light sources - compact and low cost - that will satisfy the increasing demand of the scientific community. This next generation of FELs will deliver bright X ray beams at a repetition rate of 10 Hz, of interest for the many applications that do not require very high average brightness such as available from the fourth light sources generation. The laser plasma accelerator research activities of the X-five project will also be of benefit to other fields, including medicine, radiation biology, chemistry, physics and material science, security, and of course accelerator science.