Britain adopted a cautious approach in relation to supporting the Republican government. The British also pressurised the French government not to become heavily involved. This was due to the government being afraid it would result in a wider European war. There was also an ideological reason that the British cabinet was afraid of the spread of communism. Spain also accounted for 13% of Britain's European investments and they felt these would be endangered by a rise of a revolutionary socialist regime.
In 1936, Azana sought support from the LW Popular Front in France, headed by Leon Blum. Blum was initially in favour of the idea, agreeing on the 20th July 1936 to send a shipment of armaments. However, he changed his mind and on the 9th August 1936 the French government prohibited the exportation of munitions to Spain.
France wasn't willing to support the Republicans unless Britain was also ready to intervene. In the 1930s, Britain and France followed a policy of appeasement to try and prevent war with Germany. They feared direct involvement in the Spanish Civil War would endanger the policy of appeasement and lead to war with Germany.
The French government, unwilling to intervene directly, proposed a scheme which it hoped might help indirectly. This was an agreement of non-intervention to be signed by all the major European powers. The Non-Intervention Committee met for the first time in London in August 1936. France, Britain and 27 other countries, including Italy, Germany and Russia, signed a non-intervention pact regarding their involvement in the Spanish Civil War.
The French hoped that Germany and Italy would honour the agreement and refuse to supply the Nationalists. In 1936, the Republicans had both territorial and industrial advantages so the French hoped the non-intervention pact would be enough to promote a Republican victory.
However, the policy of non-intervention favoured the Nationalists. Britain and France honoured the agreement and sent no military aid to either side. Germany and Italy ignored the treaty and continued to send aid to Franco. The Soviet Union sent some aid to the republic, but Stalin demanded a high price.