HELD
The offer to buy amounted to an inducement to ESV to commit a crime. It was therefore an attempted incitement.

COMMENT
This case decides that incitement can occur even where the incitor does not initiate the suggestion but is invited to do so by the person incited. [Semple Piggot Rochez]

A person who responds to an advertisement offering to supply indecent photographs of children by placing an order for the supply of such photographs may be charged with inciting the commission of an offence of distribution of indecent photographs of children or with an attempt at such incitement (depending on whether the order was received by the incitee); if the incitee supplied photographs pursuant to the order, that supply would constitute a separate and distinct offence of distribution from any offence that might have been committed by virtue of the publication of the advertisement itself. [Hamiltons]

[Hamiltons]
http://www.hamiltons-solicitors.co.uk/archive-docs/operation-ore.htm

Found in reference material for London University External students at Recent Developments in Laws:

‘Attempt to incite’: the offence was upheld in R v Goldman [2001] Crim LR 822 though one wonders why the full offence of incitement was not charged.

If I publish an article inciting that some particular person be killed in a newspaper and that newspaper is never read by anyone, have I done something which is merely preparatory to the actual crime of incitement? I do no more (nor any less) if a person reads the newspaper than if they do not.