The potential of ep collision to prospect for anomalous Wtb vertex is discu
ssed from the single top quark production process ep --> t<(<nu>)over bar>
+ X for TESLA + HERAp and CLIC + LHC energies. Sensitivities to anomalous c
ouplings F-2L and F-2R, in the case of CLIC + LHC, are shown to be comparab
le with LHC. (C) 2001 Elsevier Science B.V. All rights reserved.