British officials had been using intermediaries to try to secure Dyer's release, and had asked the media to comply with a media blackout to avoid increasing his "value" as a hostage. The government generally believes publicity can have a negative effect on such cases.
Source: http://www.guardian.co.uk/world/2009/jun/03/edwin-dyer-hostage-killed-al-qaida
Well, there goes that theory! Doesn't matter whether it gets publicity or not - they're still going to kill the hostage.