[1][3] Despite his comfortable upbringing and his high social status, Pearson was a radical, and throughout his life he fought a number of campaigns on progressive and reforming issues including the removal from the Monument inscription blaming the Great Fire of London on Catholics, the abolition of packed special jury lists for political trials, and the overturning of the ban on Jews becoming brokers in the City.

[6] He unsuccessfully attempted to break the local monopolies developed by the gas companies, calling for the distribution pipework to be owned collectively by the consumers.

[7][9] Recognising the increasing congestion in the City and its rapidly growing suburbs, Pearson published a pamphlet in 1845 calling for the construction of an underground railway through the Fleet valley to Farringdon.

[15]Many of the proposed schemes were rejected, but the Commission did recommend that a railway be constructed linking the termini with the docks and the General Post Office at St. Martin's Le Grand.

[19] Pearson died of dropsy on 14 September 1862 at his home at West Hill, Wandsworth,[1] and did not live to see the opening of the Metropolitan Railway on 10 January 1863.

[1] Transport writer Christian Wolmar considers Pearson to have "by far the best claim" to be the first to propose the idea of an underground railway to deal with London's congestion problem.

[21] Michael Robbins considers that "without Pearson's constant advocacy–his gadfly conduct, which he managed to combine with holding high office in the City of London–the Metropolitan Railway, the first of its kind in the world, and the nucleus of London's underground system, could not have come into existence when it did.

[22] The Metropolitan Railway and the network of underground lines that grew from it was the first in the world and the idea was not adopted elsewhere until 1896 when the Budapest Metro and the Glasgow Subway were both opened.

[23] The expansion of the capital that the underground network and its suburban surface extensions enabled was considerable and rapid and helped the population of what is now Greater London to increase from 3,094,391 in 1861 to 6,226,494 in 1901.