French's most important role was as Commander-in-Chief (C-in-C) of the British Expeditionary Force (BEF) for the first year and a half of the First World War. He had an immediate personality clash with the French General Charles Lanrezac. After the British suffered heavy casualties at the battles of Mons and Le Cateau (where Smith-Dorrien made a stand contrary to French's wishes), French wanted to withdraw the BEF from the Allied line to refit and only agreed to take part in the First Battle of the Marne after a private meeting with the Secretary of State for War, Lord Kitchener, against whom he bore a grudge thereafter. In May 1915 he leaked information about shell shortages to the press in the hope of engineering Kitchener's removal. By summer 1915 French's command was being increasingly criticised in London by Kitchener and other members of the government, and by Haig, Robertson and other senior generals in France. After the Battle of Loos, at which French's slow release of XI Corps from reserve was blamed for the failure to achieve a decisive breakthrough on the first day, H. H. Asquith, the British Prime Minister, demanded his resignation. Haig, who was formerly French's trusted subordinate and who had saved him from bankruptcy by lending him a large sum of money in 1899, replaced him.