Question: What is the name of the widow of the earl who served as both Foreign Secretary and Prime Minster from 1955 to 1957?

Context paragraphs:
European Union (Amendment) Act 2008: The European Union (Amendment) Act 2008 (c. 7) is an Act of the Parliament of the United Kingdom.  It gives effect in the law of United Kingdom to the Lisbon Treaty, which was signed there by then-Prime Minister Gordon Brown on 14 December 2007.  The Bill was first debated in the House of Commons on 21 January 2008, and passed its second reading that day by a vote of 362-224; Prime Minister Gordon Brown was absent that day, and left the Bill to be defended by the then Foreign Secretary David Miliband who introduced it to the House of Commons.  A Conservative amendment led by the then Shadow Foreign Secretary William Hague to hold a UK-wide referendum on final approval the Lisbon Treaty was defeated by the Labour Government in a Committee stage debate on 5 March 2008 by 311-248 in the House of Commons.  The enactment via royal assent came on 19 June 2008.  The Act does not actually ratify the treaty; it merely adds the Lisbon Treaty to the treaties listed in section 1(2) of the European Communities Act 1972.  The actual ratification by the United Kingdom of the treaty took place when the British Government deposited the instruments of ratification in Rome on 16 July 2008.

Shadow Foreign Secretary: In British politics, the shadow foreign secretary is a position within the opposition's shadow cabinet that deals mainly with issues surrounding the Foreign Office.  If elected, the person designated as shadow foreign secretary may be slated to serve as the new Foreign Secretary.

Clarissa Eden: Anne Clarissa Eden, Dowager Countess of Avon ("née" Spencer-Churchill; born 28 June 1920) is the widow of Anthony Eden, 1st Earl of Avon (1897–1977), who was British Prime Minister from 1955 to 1957.  She married Eden in 1952, becoming Lady Eden in 1954 when he was made a Knight of the Garter, and then becoming Countess of Avon in 1961 on her husband's elevation to the peerage.  She is also the niece of the prime minister Winston Churchill.  Her memoir, sub-titled "From Churchill to Eden", was published in 2007 under the name of Clarissa Eden.

Anthony Eden hat: An "Anthony Eden" hat, or simply an "Anthony Eden", was a silk-brimmed, black felt Homburg of the kind favoured in the 1930s by Anthony Eden, later 1st Earl of Avon (1897–1977).  Eden was a Cabinet Minister in the British National Government, holding the offices of Lord Privy Seal from 1934–1935 and Foreign Secretary 1935 to 1938.  He was later Dominions Secretary from 1939–1940, War Secretary in 1940, Foreign Secretary from 1940–1945 and 1951–1955, and Prime Minister 1955 to 1957.

Earl Canning: Earl Canning was a title in the Peerage of the United Kingdom.  It was created in 1859 for the Conservative politician and then Viceroy of India, Charles Canning, 2nd Viscount Canning.  He was the third and youngest son of the noted politician George Canning, Foreign Secretary from 1807 to 1809 and from 1822 to 1827 and Chancellor of the Exchequer and Prime Minister of the United Kingdom in 1827.  In 1828 George Canning's widow Joan, was raised to the Peerage of the United Kingdom in honour of her husband as Viscountess Canning, of Kilbraham in the County of Kilkenny, with remainder to the heirs male of her body by her late husband.  Lady Canning was the daughter of Major-General John Scott.

Anthony Crosland: Charles Anthony Raven Crosland (29 August 1918 – 19 February 1977), otherwise Tony Crosland or C.A.R. Crosland, was a British Labour Party politician and author.  He served as Member of Parliament for South Gloucestershire and later for Great Grimsby.  Throughout his long career he occupied the cabinet positions of Secretary of State for Education and Science, President of the Board of Trade, Secretary of State for Local Government and Regional Planning and Foreign Secretary.  A prominent socialist intellectual, he became one of the Labour Party's revisionists on the right, as an intellectual leader of Gaitskellism.  His highly influential book "The Future of Socialism" (1956) argued against many Marxist notions and Labour Party orthodoxy that public ownership was essential to make socialism work.  He offered positive alternatives to both right and left wings of his Labour Party.  He questioned the need for public ownership of the means of production – the classic socialist formulation – and argued instead for making the highest priority the end of poverty and improved public services.  He led the Labour battle to replace grammar schools with comprehensive schools that did not sort students at age 11.  As foreign secretary he promoted détente with the Soviet Union.

Great Offices of State: The Great Offices of State in the United Kingdom are the four most senior and prestigious posts in the British government.  They are the Prime Minister, Chancellor of the Exchequer, Foreign Secretary and Home Secretary.  According to convention, when the Prime Minister names his or her Cabinet, either after a general election or a mid-term reshuffle, the first Cabinet ministers to be announced are the Chancellor, the Foreign Secretary and the Home Secretary.

Friedrich zu Limburg-Stirum: Friedrich Wilhelm Graf zu Limburg-Stirum (6 August 1835, The Hague – 27 October 1912) was a German diplomat and politician who served as acting Foreign Secretary and head of the Foreign Office from September 1880 to 25 June 1881.  Having until then served as Deputy Secretary of State in the Foreign Office, he was appointed as Foreign Secretary after Chlodwig, Prince of Hohenlohe-Schillingsfürst resigned from this position.  He was subsequently succeeded by Clemens Busch as acting Secretary.

Shyam Saran: Shyam Saran (born 4 September 1946) is an Indian career diplomat.  He joined the Indian Foreign Service in 1970 and rose to become the Foreign Secretary to the Government of India.  Prior to his appointment as the Foreign Secretary he served as India's ambassador to Myanmar, Indonesia and Nepal and as High Commissioner to Mauritius.  Upon completion of his tenure as the Foreign Secretary he was appointed Prime Minister’s Special Envoy for Indo-US civil nuclear issues and later as Special Envoy and Chief Negotiator on Climate Change.

Anthony Eden: Robert Anthony Eden, 1st Earl of Avon, (12 June 1897 – 14 January 1977) was a British Conservative politician who served three periods as Foreign Secretary and then a relatively brief term as Prime Minister of the United Kingdom from 1955 to 1957.

Supporting paragraphs: Clarissa Eden Anthony Eden
Answer: Anne Clarissa Eden