Ernest Bevin luuuuurved the Marshall Plan.
Basically, his involvement started when he heard the speech on the radio, and instantly called his French counterpart (Georges Bidault, if you were curious), and was like, "We have to get on this." The two of them got to work drafting European acceptance to the plan.
Bevin came out of humble origins with very little formal education. He helped found the Transport and General Workers Union (which later became one of the biggest unions in the U.K.), and from there, got into politics on the left wing Labour side of things.
He was a staunch enemy of communism, helped create NATO and the state of Israel. So he was pretty important. With regards to the Marshall Plan, his chief role was in rolling out the red carpet. This quick acceptance, though, also helped keep the allies of the United States, United Kingdom, and France all together as the three musketeers of postwar buddies. This is more notable when you remember that a little over a hundred years before this, most of history was Britain and France hating each other.