Some people may be alarmed that the BBC has decided to make the Frozen Planet's climate change episode ("On Thin Ice") optional when it comes to overseas sales, but the reality is that many commercial broadcasters are often very conservative in terms of what they are willing to show on their channel(s).

This is typically the case in the US, of which I suspect this particular decision is specifically aimed at, and BBC Worldwide is canny enough to realise that Frozen Planet sales would be given the cold shoulder (or at least made more awkward) as a consequence.

Whilst it may be easy to criticise the BBC (and BBC Worldwide) for allowing such acts of censorship to take place, this form of selective marketing has taken place for years, especially as certain countries may not share the same 'liberal' values of our Western European neighbours hence requiring extensive edits or dropped episode(s).

If the complete series including "On Thin Ice" was only offered on a take it or leave it basis, certain broadcasters would be very reluctant to effectively pay for an episode they have no intention of showing, and given the intense competition for nature and wildlife documentaries it's a price that BBC Worldwide is willing to pay.

Anyway, it's perhaps ironic that anyone attempting to obtain the Frozen Planet series by 'illegal' means may also end up with the climate change episode as a consequence, and withholding the episode from being broadcast in certain countries could also make it more desirable to collectors.

This might not be the sort of thing that the BBC should normally be doing as a matter of course, but perhaps the BBC could consider revising "On Thin Ice" to make it more sensationalist along the lines of "The programme they tried to ban, containing facts they don't want you to know".

After all, certain TV channels don't seem to flinch at the prospect of showing programmes which claim that the manned moon landings never happened.