Final answer:
John Maynard Keynes was the British economist who advocated for government spending to stimulate the economy during downturns. His Keynesian economics deeply influenced the New Deal programs during the Great Depression and aimed to boost employment and consumer spending.
Step-by-step explanation:
The British economist who advocated the use of government spending during economic downturns to stimulate the economy was John Maynard Keynes. His influence was particularly notable on the New Deal programs implemented by President Franklin D. Roosevelt during the Great Depression. Keynesian economics proposed that during economic slumps, the government should increase spending and cut taxes to boost employment and consumer spending. Conversely, Keynes suggested that in times of economic prosperity, the government should decrease spending and increase taxes to prevent inflation.
Keynes' ideas were revolutionary at the time, as they suggested a strong and proactive role for the government in managing the economy. His theory is credited with helping to pull the United States out of the Great Depression through New Deal programs such as the Works Progress Administration (WPA). These programs were responsible for injecting capital into the economy, creating jobs, and increasing consumer spending, which in turn stimulated economic growth.