furiousgeorge, there are those who identify on sight alone and those that identify according to the presence of diagnostic features. Having said that, sight recognition invariably plays a big part in the initial process of identification of those that look for diagnostic features. I know which ID I'd be more comfortable with.
There are only two snakes with that have that sort of pattern and colour combined with strongly keeled dorsal scales… the Rough-scaled Snake and the Keelback. I believe that the photo is of a Keelback (Tropidonophis mairii). Based on pattern and colour alone, at a glance one could quite easily identify this snake as a Rough–scaled Snake. However, the degree of irregularity of the banding along the lateral areas is typical of Keelbacks, whereas Rough-scaled Snakes are much more consistent in their bands. The presence of a loreal scale is not quite discernible under magnification. What can be seen is the dark edges on the upper labial scales, particularly those below the eye, which do not occur with Rough-scaled Snakes. In addition, jaws of Keelbacks exhibit an upwards curve at the joint, as apparent in the photo, whereas Rough-scales have a straight jaw line. The relative size of the eye has been mentioned as Keelbacks do have a proportionately larger eye than Rough-scaled Snakes. Without a reference measure this can be problematic in using as a diagnostic feature.
Blue