417 Sir Frederick Stewart, Minister for External Affairs, to Mr R. G. Casey, Minister to the United States
Cablegram 473 22 April 1941,
IMMEDIATE MOST SECRET
Your telegram 283 and Latham's No. 26 to you.  On receipt of report regarding Singapore we made known to United Kingdom Government through Prime Minister  great importance which we attach to contemplated joint declaration by British Empire, United States and Netherlands East Indies that an attack on Netherlands East Indies or on British possessions in the Far East would be regarded as a casus belli by both the United States and the British Empire. You are no doubt aware that proposal to this effect was raised in conversation by Halifax  with Hull  on March 5th.
It is now understood that United Kingdom Government through Halifax and Winant  has taken steps to press in Washington for joint declaration in above terms. Desire you should make concurrently strongest possible representations on behalf of Commonwealth Government in same sense. In view of position Middle East regard matter as of extreme importance and urgency.