  Gravitational lensing of very high energy photons has recently been observed
in the JVAS B0218+357 strong lensing system. This observation opens the
possibility of performing a test of gravity at high energy by comparing the
difference in propagation time of high energy photons over different travel
paths. The time delay is computed in the framework of a LIV (Lorentz Invariance
Violation) extension of the equations of motion of photons in the field of a
massive object. However, the method obtained can be transposed to other models
of gravity at high energy. The potential for constraining high energy gravity
with future observations of JVAS B0218+357 is discussed. The bounds on the LIV
energy scale will not be competitive with other astrophysical bounds such as
those coming from AGN and GRB flares. However, these bounds are free of any
assumption on the emission process.
