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The 2-m robotic Liverpool Telescope (LT) reacted promptly to thehigh-redshift (z=4.048) gamma-ray burst GRB 060206. The afterglow wasidentified automatically and multicolor r'i'z' imaging was triggered withouthuman intervention. Combining our data with those obtained from laterfollow-ups provides a well-sampled optical light-curve from 5 minutes to >2dafter the gamma event. The light-curve is highly structured with at least threebumps evident in the first 75 minutes, including a major rebrightening(Delta_r'=-1.6 at t=3000s), interpreted as late energy injection. At early time(t=440s), we find evidence for fast (Delta t_(rest)<4s<<t) variability,indicating on-going internal-engine activity. We emphasise that a low redshiftGRB (z<1) with similar intrinsic properties would have been interpretedcompletely differently due to undersampling of the light curve in the restframe at early times; the light-curve behaviour of GRB 060206 should thereforenot be considered peculiar. Finally, although the observed late-time steepeningof the optical light curve resembles a jet break if taken in isolation, thelack of a corresponding change in the X-ray slope rules out a jet-breakinterpretation. Traditionally, GRB jet breaks have been inferred from opticaldata in the absence of simultaneous X-ray data. We suggest therefore thatcurrent estimates of the jet opening angle distribution might be biased byevents like GRB060206. Consequently, the GRB explosion energy distribution andevent rates may have to be revised.Comment: 9 pages, 5 figures, Submitted to Ap

High‐Quality Early‐Time Light Curves of GRB 060206: Implications for Gamma‐Ray Burst Environments and Energetics