Apart from his legal and political careers, Haldane was an influential writer on philosophy, in recognition of which he was elected a Fellow of the British Academy in 1914.

[3] A cousin, the Whig politician Lord Camperdown encouraged the young barrister into standing as a Liberal at the General Election of 1880.

In 1881 Haldane met H. H. Asquith, and they soon became firm friends often meeting at the Blue Post Public house on Cork Street.

In 1888, he courted Emma Valentine Ferguson, sister of his Liberal party friend, Ronald Munro-Ferguson; she broke off the engagement and subsequently lampooned him in her novel Betsy in 1892.

Haldane remained an ally of Asquith and Grey in the Liberal Imperialist wing of the party, followers of Lord Rosebery rather than of Sir William Harcourt.

[3] On 11 August 1902, Haldane was admitted to the Privy Council,[15] following an announcement of the King's intention to make the appointment in the 1902 Coronation Honours list, published in June that year.

[18] However, the plot (called "The Relugas Compact" after Grey's Scottish lodge where the men met) collapsed when Asquith agreed to serve as Chancellor of the Exchequer under Campbell-Bannerman.

[22] As early as January 1906 Haldane was persuaded by fellow Liberal Imperialist Edward Grey to begin planning for a Continental war in support of the French against the Germans.

A fluent German-speaker, Haldane was lulled into a false sense of security believing 'like a bear with a sore head' that he had won a great deal.

[28] The Official Historian Brigadier James Edmonds later wrote that "in every respect the Expeditionary Force of 1914 was incomparably the best trained, best organised and best equipped British Army ever to leave these shores"[29] Haldane set up the Imperial General Staff.

[30] Haldane's reforms also created the Territorial Force of 14 divisions (the original plan was for 28) and 14 mounted Yeomanry brigades at home,[28] the Officer Training Corps and the Special Reserve.

A. Spender later wrote of how Haldane got the best work out of an able but verbally-incoherent soldier (thought to refer to Haig) by not scoring verbal points off him, as many politicians would have done.

His reforms re-oriented British military policy, revamped army organization along the lines of the German General Staff, upgraded the training of the auxiliary forces, and created an efficient and economically run service.

"[34] During the constitutional and budget crisis of 1909–11, Haldane advised his friend and Prime Minister, Asquith on the legal niceties of his stance towards the monarch, who was outraged at the firebrand speeches from Churchill and Lloyd George.

[citation needed] Two elections ensued, one in January and another in December 1910, before in 1911 he was raised to the peerage as Viscount Haldane, of Cloan in the County of Perth.

[37] 1912 saw the unsuccessful attempt of the Haldane Mission, an effort to quell the friction between Britain and Germany arising because of their escalating naval arms race.

Haldane was one of the first members of the Cabinet to recognise that war with Germany was inevitable and persuaded Asquith to mobilise by assembly of the Army Council on 3 August.

[42] Following the outbreak of the First World War Haldane was falsely accused of pro-German sympathies, in July 1914, for hosting Albert Ballin, a German shipping magnate and unofficial mediator between Germany and Britain.

The accusations were widely believed[citation needed] and were even echoed in a popular music hall song ("All dressed up and nowhere to go") in the revue "Mr Manhattan".

He was harried in particular by Beaverbrook's Daily Express, which gave great publicity to the claim by Professor Onkel of Heidelberg that he had said "Germany was his spiritual home".

[citation needed] As Lord Chancellor, Haldane was a member of the Judicial Committee of the Privy Council, at that time the court of last resort for the Empire.

He sat on several cases from Canada dealing with the division of powers between the federal and provincial governments under the Canadian Constitution, particularly the interplay between sections 91 and 92 of the British North America Act 1867.

He gave the decision for the Judicial Committee in several of those cases, and showed a marked tendency to favour the provincial powers at the expense of the federal government.

The philosophy of 'national efficiency' was central feature of the Hegelian complex, and the ideas of Schopenhauer, he had learnt on the continent, that accentuated freedom and decentralisation from an historicist's perspective.

[60] Haldane was a member of the Coefficients dining club of social reformers set up in 1902 by the Fabian campaigners Sidney and Beatrice Webb.

On promoting Churchill to First Lord of the Admiralty, Asquith advised him to seek Haldane's advice at a meeting held at Archerfield, North Berwick.

"The Reign of Relativity" combined Haldane's love of all things German expressed by Goethe and his works, with the Hegelian military-industrial complex.

The rising tide of New Liberalism and moral realism was for Haldane, Hegel's philological precept to improve behaviour, using the empiricism of scientific data as a proof.

In November 1923 Lord Birkenhead, the Conservative politician, praised Haldane's contribution to Britain's preparedness for the First World War: In the welter of sentimentality, amid which Great Britain might easily have mouldered into ruin, my valued colleague, Lord Haldane, presented a figure alike interesting, individual, and arresting.

[5] The military historian Correlli Barnett claimed that Haldane had "all-round personal talents far exceeding those of his predecessors" as Secretary of State for War and that he was "a man of first-class intellect and wide education".