The East London large-format specialist produced the shimmering posters for the movie, which is released tomorrow (29 July), on a background of a pink and blue opalescent film mounted on top of a metallic foil giving a mirror effect.

Sales director Daniel Pattison said: "To complicate the matter we had to laminate the product to standard Viacom-approved transit vinyl for application onto the buses. This was without doubt the most complex bus side we have produced this year."

The panels were then screen printed with a selective white ink and a standard four-colour process. Three other versions of the bus-side were printed using a specially formulated dayglo ink.

Augustus Martin has also produced the golden tickets for a tie-in promotion currently running with Nestl. Finders of the lucky tickets, which mirror the plot of Roald Dahl's original book, will win a trip to a chocolate factory in the US.