To what extent was Labour's defeat in the 1959 General Election the result of internal divisions in the party?

The Conservatives won the general election in 1951, and remained in power for the next 13 years, winning the next two general elections in 1955 and 1959. The election was won with Churchill (1951-1955) replaced by Anthony Eden (1955-57) who was later replaced by Harold MacMillan (1957-63). There are two main arguments to this question, the reason why the Conservatives remained in power or the reasons why Labour didn't regain power?

Reasons why Lavour were defeated in 1959?

• ''Many of the reasons for defeat in 1959 had stemmed from the reasons apparent in 1951''
• Labour fell from power in 1951 because of the divisions in the party-By 1959 Labour had achieved much of what it had promised in its election. Morrison (and the majority of the party) wanted consolidation, whereas Bevan and Labour fundamentalists wanted further reform e.g. more nationalisation. Gaitskell introduced charges for spectacles and dentures and Bevan resigned alongsidde Harold Wilson and John Freeman. This, split between 'moderate' and socialist/ leftward leaning in the party made the election campaign weak.
• Most of its ministers (those with experience) had been in office for at least 10 years, old age and illness weakened the party. ''Labour had run out of steam''.
• Labour policies were becoming weary, rationing, high taxation, the drab austerity and the benefits of nationalisation were questioned. 
• Labour had introduced some of the greatest social reforms. However, not everyone agreed with these reforms, Margaret Thatcher called Labour reforms 'pernicious' and at West Dartford the local candidate insisted that another Labour government would produce 'straight totalitarianism' .
• The electoral system was a key factor in the Labour defeat. In 1951, Labour won large majorities and essentially votes were 'wasted' in safe constituencies whereas Conservatives gained many marginal votes. This was due to the 1948 and the 1949 Representtion of People Acts which substantially redrew constituency boundaries to account for changing population patterns, to Labour's disadvantage. Postal voting was also introduced for the first time, and according to H. Morrison these were cast 10-1 in favour of the Conservatives.
• Liberal Decline- the Liberald put up fewer candidates, and Liberal voters, voted Conservative where no Liberal candidate stood.

Labour stayed out of power in 1959 because... 

Division in the party

•  Antagonism between Bevanites and Gaitskellites came from different views of how Labour should get back in power. Bevanites opposed what they thought was a retreat from Socialism. Gaitskellites were adament that the conditions of British society had changed and Labour had seen beyond Clause Four and support the working class. Neither offered positive policies for the future other than defence and abandoning Clause Four. 
• Defence Policy- the official Labour line was to go along with the government's rearmament in an attempt to keep up with the USA and USSR, Bevan and his supporters- criticised it bitterly; Bevan was on the verge of being expelled from the party after his attacks on Attlee. 'Bevanites' were a continual source of trouble to the Party Leadership. Bevan himself resigned from the shadow cabinet…