Question: Which party did the English Prime Minister and subject of Barbara Learning lead from 1940 to 1955?

Sir Winston Leonard Spencer-Churchill, {'1': ", '2': ", '3': ", '4': "} (30 November 187424 January 1965) was a British statesman, army officer, and writer.  He served as Prime Minister of the United Kingdom from 1940 to 1945 and again from 1951 to 1955.  As a Member of Parliament (MP), he represented five constituencies over the course of his career.  He led the Conservative Party for fifteen years from 1940 to 1955.  As Prime Minister, Churchill led Britain to victory during World War II. <SEP> Clement Richard Attlee, 1st Earl Attlee, {'1': ", '2': ", '3': ", '4': "} (3 January 1883 – 8 October 1967) was a British Labour politician who served as Prime Minister of the United Kingdom from 1945 to 1951 and Leader of the Labour Party from 1935 to 1955.  In 1940, Attlee took Labour into the wartime coalition government and served under Winston Churchill, becoming the first person to hold the office of Deputy Prime Minister of the United Kingdom.  He went on to lead the Labour Party to an unexpected landslide victory at the 1945 general election; forming the first Labour majority government, and a mandate to implement its postwar reforms.  The 12.0% national swing from the Conservatives to Labour was unprecedented at that time and remains the largest ever achieved by any party at a general election in British electoral history.  He was re-elected with a narrow majority at the 1950 general election.  In the following year, Attlee called a snap general election, hoping to increase his parliamentary majority.  However, he was narrowly defeated by the Conservatives under the leadership of Winston Churchill; despite winning the most votes of any political party in any general election in British political history until the Conservative Party's fourth consecutive victory in 1992.  Attlee remains the longest-ever serving Leader of the Labour Party. <SEP> Barbara Leaming is a bestselling American biographer, whose subjects have included Roman Polanski, Orson Welles, Rita Hayworth, Marilyn Monroe, John F. Kennedy, Winston Churchill, and Jacqueline Kennedy Onassis. <SEP> Han Myeong-sook (born March 24, 1944; Korean: 한명숙 ] ) was the Prime Minister of South Korea from April 2006 to March 2007.  She is South Korea's first female prime minister (second female prime minister overall if the acting premiership of Chang Sang is included).  She was from the United New Democratic Party (UNDP) as a member of the Korean National Assembly (representative) for Ilsan-gab, and is a graduate of Ewha Womans University in Seoul with a degree in French literature.  She resigned as Prime Minister on March 7, 2007 and declared her presidential candidacy.  But she did not succeed in the nominations.  In 2008 she ran for parliament, but was not elected.  However, in January 2012 she was elected leader of the main oppositional Democratic United Party (DUP) before the April legislative elections and became a member of parliament.  But the liberals did not manage to defeat the ruling Saenuri Party and Han stepped down as party leader in April 2012.  In August 2015, Han was convicted of receiving illegal donations at the amount of 900 million KRW, and sentence to two years in prison.  She is ineligible to run for public office for ten years after her prison term.  She became the first former prime minister of the Republic of Korea to serve a prison time.