In the current work we investigate the propagation of electromagnetic waves in the field of gravitational waves .
Starting with simple case of an electromagnetic wave travelling in the field of a plane monochromatic gravitational wave we introduce the concept of surfing effect and analyze its physical consequences .
We then generalize these results to an arbitrary gravitational wave field .
We show that , due to the transverse nature of gravitational waves , the surfing effect leads to significant observable consequences only if the velocity of gravitational waves deviates from speed of light .
This fact can help to place an upper limit on the deviation of gravitational wave velocity from speed of light .
The micro-arcsecond resolution promised by the upcoming precision interferometry experiments allow to place stringent upper limits on \epsilon = ( v _ { gw } - c ) / c as a function of the energy density parameter for gravitational waves \Omega _ { gw } .
For \Omega _ { gw } \approx 10 ^ { -10 } this limit amounts to \epsilon \lesssim 2 \cdot 10 ^ { -2 } .