From a BBC History piece linked to by Jim.

"Despite many myths after the war, there was in 1914 no fully developed British government organisation or plan for propaganda or the manipulation of public opinion. Just as with the army recruiting drives, so the posters, newspaper proclamations and claims of German 'atrocities' were the product of a complex mix of spontaneous action, national and local politics, and business initiatives. Only as the war continued did the government start to extend its grip on propaganda and public opinion, as on many other aspects of society"

"The power of the national press (London-based except for the Manchester Guardian) was so great that as long as it avoided outright confrontation with the government, it was left to be largely self-regulating. The policy of most national newspapers was that of the governing class itself: to support the war effort, but to reserve the right to criticise government policies. The government paid much less attention to the regional or local press, which was largely free to write what it wanted. In particular the habit continued, established in earlier wars, of soldiers' letters being passed on to local newspapers for publication."

Jim's link again.
http://www.bbc.co.uk/history/british/britain_wwone/war_media_01.shtml
Thanks Jim.