Owing to public pressure, the British government was pushed towards declaring war with Spain in 1739. Britain began with a success at Porto Bello. However the war effort soon stalled, and Pitt alleged that the government was not prosecuting the war effectively—demonstrated by the fact that the British waited two years before taking further offensive action fearing that further British victories would provoke the French into declaring war. When they did so, a failed attack was made on the South American port of Cartagena which left thousands of British troops dead, over half from disease, and cost many ships. The decision to attack during the rainy season was held as further evidence of the government's incompetence.