The brick tax was a property tax introduced in Great Britain in 1784, during the reign of King George III, to help pay for the wars in the American Colonies. Bricks were initially taxed at 4s per thousand. To mitigate the effect of the tax, manufacturers began to increase the size of their bricks, up to a maximum of 11 inches × 5 inches × 3 1⁄2 inches (280 mm × 125 mm × 80 mm). In response, the government introduced a maximum volume for a brick, at 150 cubic inches (2,500 cm3). The level of taxation was increased in 1794, 1797, and 1805, peaking at 5s 10d per thousand bricks.
One of the consequences of the brick tax was that some minor brick producers went out of business, forced to sell their stock to meet tax arrears. It also had an effect on architecture, with many areas returning to the use of timber and weatherboarding in house construction.. In Fenland,local clay was used to create unfired mud walls.  "Mathematical tiles" or "brick tiles" were a way to imitate a brickwork facade on timber-framed buildings. The brick tax was abolished in 1850, by which time it was considered to be a detriment to industrial development.
Many buildings built by Joseph Wilkes in Measham, Leicestershire, were built with bricks manufactured by his own brickyard, including his Jumb or Gob bricks, for which he is well known. These double sized bricks (measured on one of the Ashby Canal warehouses in Measham as 9 1⁄4 inches x 4 1⁄4 inches x 4 1⁄4 inches (235 mm × 108 mm × 108 mm)) were manufactured between 1784 and 1803 and were intended to lessen the burden of the brick tax. A few buildings exhibiting Wilkes' oversized bricks can still be seen in Measham and the surrounding area today.