London stock brick

London stock brick is the type of handmade brick which was used for the majority of building work in London and South East England until the increase in the use of Flettons and other machine-made bricks in the early 20th century. Its distinctive yellow colour is due to the addition of chalk. Another important admixture is 'spanish', which is made up of ash and cinders from incinerated waste and rubbish. The spanish ignites on firing and reduces fuel costs at the firing stage. London Stocks are still made in comparatively small quantities in traditional brickworks, mainly in Kent and Sussex, for heritage work, and machine-made versions are available for use where a cheaper approximation to the traditional product is acceptable.^[1] Red stock bricks are also fairly common, but only the yellow or brown bricks are usually known as London stocks.