What appeasement have britain the chance to build up

"Appeasement is a diplomatic policy aimed at avoiding war by making concessions to an aggressor." 

Prior to World War Two the British and French tried Appeasing Hitler by agreeing to return the Sudentenland for example to Germany and didn't interfere or prevent the Germans from reoccupying the Rhineland. 
http://en.wikipedia.org/wiki/Appeasement 
In the process by avoiding conflict the Brits were able to ready for a possible war and better able to deal with it once it happened; example being perfecting radar prior to the Battle of Britain. 

Hope that helps :)

Its a whole new world