Mackintosh wrote to Newbery to ask for a reference in order to help resolve his difficulties with the authorities following his arrest on suspicion of spying for the enemy during his time in Walberswick 1914-15.
The original is now in the archive of The Glasgow School of Art.
Dear Mr Newbery
I am writing to ask if you will please write me a letter setting forth your knowledge of me personally and professionally. We have to lay our case before the Home Secretary and among others I want a letter from you. Please send it here as soon as possible as every days delay is unfortunate You can believe me when I say that neither of us have done anything here to deserve being placed in our present unfortunate position I feel that a simple statement from you would be of great value It has given me much pleasure to hear that you are well and strong again
C. R. Mackintosh