He steered the development of the London Underground's corporate identity by commissioning eye-catching commercial art, graphic design and modern architecture, establishing a highly recognisable brand, including the first versions of the roundel and typeface still used today.

Under his direction, the UERL's Underground network and associated bus services expanded considerably, reaching out into new areas and stimulating the growth of London's suburbs.

For the government, Pick prepared the transport plan for the mass evacuation of civilians from London at the outbreak of war and produced reports on the wartime use of canals and ports.

[3] As a child, Pick was bookish, preferring to read and build collections of moths and butterflies and objects found on the beach rather than take part in sports.

The spread of street-level electric trams and motor buses, replacing slower, horse-drawn road transport, also took a large number of passengers away from the trains.

[23] Pick introduced a common advertising policy, improving the appearance of stations by standardising poster sizes, limiting the number used and controlling their positioning.

Pick standardised commercial poster sizes on printers' double crown sheets, arranging these in organised groups to enable the station name to be easily seen.

"[28][note 7] To make the Underground Group's posters and signage more distinctive, he commissioned calligrapher and typographer Edward Johnston to design a clear new typeface.

[20][30] Pick specified to Johnston in 1913 that he wanted a typeface that would ensure that the Underground Group's posters would not be mistaken for advertisements; it should have "the bold simplicity of the authentic lettering of the finest periods" and belong "unmistakably to the twentieth century".

[32] In conjunction with his changes to poster display arrangements, Pick experimented with the positioning and sizing of station name signs on platforms, which were often inadequate in number or poorly placed.

In 1908, he settled on an arrangement where the sign was backed by a red disc to make it stand out clearly, creating the "bulls-eye" device – the earliest form of what is today known as the roundel.

[20][36] In 1919, with a return to normality after the First World War, Pick began developing plans to extend the Underground network out into suburbs that lacked adequate transport services.

[42] Wanting to make maximum use of the government's financial backing, which was only available for a limited period, Pick did not have time to press the Underground's case for these extensions.

The railway companies challenged the need for a new service, claiming it would simply drain passengers from their own trains and that any extension should only run as far as Tooting, but Pick was able to counter their arguments and negotiated a compromise settlement to extend the C&SLR as far as Morden.

From 1922, a series of press campaigns called for the improvement of services at the GNR's Finsbury Park station where interchanges between tube lines, mainline trains, buses and trams were notoriously bad.

[49] The approval also included complementary extensions of the Piccadilly tube from its western terminus at Hammersmith to supplement District Railway services to Hounslow and South Harrow.

[51] To ensure the most efficient integration between the new tube line and the UERL's bus and tram operations, the stations were located further apart than in central areas and where road transport services could be arranged to deliver and collect the most passengers.

"[60] Amongst Pick's next commissions for Holden were the redesign of Piccadilly Circus station (1925–28), where a wide subterranean concourse and ticket hall were built beneath the road junction,[note 14] and the Underground Group's new headquarters building at 55 Broadway, St James's (1925–1929).

The nudity and primitive carving of Day and Night by Jacob Epstein led to calls for them to be removed from the building and the board of the Underground Group considered replacing them with new sculptures by another artist.

To decide what this new type should look like, he and Holden made a short tour of Germany, Denmark, Sweden and the Netherlands in July and August 1930 to see the latest developments in modern architecture.

[67] Although the architecture in Denmark was not considered remarkable, Pick was impressed with the way in which designers there were often responsible for all elements of a building including the interior fixtures and fittings.

Through his improvements in the UERL's advertising and branding, Pick was considered by many of its members to be taking a practical lead in achieving the organisation's aims and he was soon lecturing on the subject, giving talks during 1916 and 1917 at the Art Workers Guild in London, at the Royal Scottish Academy in Edinburgh and elsewhere.

[89] He wrote and lectured extensively on this subject during the 1920s and 1930s including presenting a 14,000-word paper to the Institute of Transport in 1927 and addressing the International Housing and Town Planning Congress in 1939.

[93] He returned to the subject in lectures he gave in the 1930s when he outlined his concern that at some not too distant point progress in civilisation would come to a natural end and a stable condition would arise where, he believed, it would be hard to maintain creativity and an entropic decline would follow.

In 1917, during the First World War, Pick was appointed to be head of the Mines Directorate's Household Fuel and Lighting Department at the Board of Trade where Albert Stanley was the President.

[114][note 20] Ashfield considered that Pick possessed "a sterling character and steadfast loyalty", and "an administrative ability which was outstanding", with "a keen analytical mind which was able to seize upon essentials and then drive his way through to his goal, always strengthened by a sure knowledge of the problem and confidence in himself.

[101] Pick was widely read and was influenced by many writers on scientific, sociological and social matters including works by Alfred North Whitehead, Leonard Hobhouse, Edwin Lankester, Arthur Eddington and John Ruskin.

[note 21] The stresses of his war work took a further toll on his health and he lost two stone during his travels around the country to research his report on the canal industry.

Transport historian Christian Wolmar considers it "almost impossible to exaggerate the high regard in which [London Transport] was held during its all too brief heyday, attracting official visitors from around the world eager to learn the lessons of its success and apply them in their own countries" and that "it represented the apogee of a type of confident public administration ... with a reputation that any state organisation today would envy ... only made possible by the brilliance of its two famous leaders, Ashfield and Pick.

[130] Historian Michael Saler compared Pick's influence on London Transport to that of Lord Reith on the BBC's development during the same interwar period.