The Christmas Truce was mentioned in letters from soldiers writing home to their families.  Some of these have been published in the local press in England:

 

http://www.yorkshirepost.co.uk/news/main-topics/general-news/story-of-the-christmas-truce-a-century-on-1-7014488

 

http://www.cravenherald.co.uk/news/11694944.Barnoldswick_soldier_writes_home_of_Christmas_truce_in_the_trenches/

 

http://britishcouncil.cmail2.com/t/ViewEmail/r/AA7E58170B44C9FC2540EF23F30FEDED/B804ED7C121891D6C45D7BC1A387288D