see also Thames - Management - Customs - click here
Custom House, The ... is accessible to visitors every day during the hours of business, viz. from 9 to 4 o'clock.
The Custom House is a vast and extensive pile, standing - on the northern bank of the Thames: the general character of this edifice is plainness and solidity, with the exception of the river front, the effect of which is grand and impressive; this, together with the wings, is constructed of Portland stone; the north front - is of brick. The whole length of the building is 488 feet; its width is 107 feet; the interior is extremely plain, the finishing being confined to a judicious neatness. The Long Room is the most striking object, from its great extent and consequent grandeur of - effect, it being nearly the largest room in Europe wherein the roof has no intermediate support: it is 190 feet long by 66 feet wide, and about 55 feet high. The Quay, enlarged by a substantial embankment, forms in fine weather a beautiful promenade; - and the view of the Thames from thence is considerably enlivened in the summer by the passage of steam-boats and other vessels that are perpetually navigating this noble river.
Mogg's New Picture of London and Visitor's Guide to it Sights, 1844
CUSTOM HOUSE, LOWER THAMES STREET ... This building has a noble river frontage of 490 feet. The principal object of interest is the Long room. Open free, daily, from nine till three.
Reynolds' Shilling Coloured Map of London, 1895
THE CUSTOMS HOUSE.
Between London Bridge and the Tower, and having, separating it from the Thames, a broad quay that was for long almost the only riverside walk in London open to the public, is the Customs House. Five earlier buildings on the same site were destroyed by fire, and the present structure was erected in 1814-17, the fine fašade being designed by Sir R. Smirke. Some 2,000 officials are employed at the Customs House, and in its famous Long Room alone -190 ft. by 66 ft. - eighty clerks are habitually engaged. This is not surprising, for the trade of the Port of London is by far the greatest of any port in the world. The building, which is entered from Lower Thames Street, contains an interesting Smuggling Museum.