They saw only the bombers which escaped its protective attack.In it we'd better change its into their.What's your idea?Thanks!
My opinion is that you need to leave a space after full stops, question marks and commas.
Ah, yes, the great speech after the evacuation from Dunkirk. In this case the answer to your question is clear. "Its" refers to the Air Force. They were protecting the troops by attacking the German bombers. Some of the bombers got through and attacked the troops, but the "protective attack" by the British pilots prevented still more Germans from bombing them.
As such it must be "its" since Air Force is considered singular.