  Motivated by the compound ${\rm LiHo}_x{\rm Y}_{1-x}{\rm F}_4$, we consider
the Ising chain with random couplings and in the presence of simultaneous
random transverse and longitudinal fields, and study its low-energy properties
at zero temperature by the strong disorder renormalization group approach. In
the absence of longitudinal fields, the system exhibits a quantum-ordered and a
quantum-disordered phase separated by a critical point of infinite disorder.
When the longitudinal random field is switched on, the ordered phase vanishes
and the trajectories of the renormalization group are attracted to two
disordered fixed points: one is characteristic of the classical random field
Ising chain, the other describes the quantum disordered phase. The two
disordered phases are separated by a separatrix that starts at the infinite
disorder fixed point and near which there are strong quantum fluctuations.
