The Mark I British Army heavy tank that entered service in 1916 was agonizingly slow to move, crawling along at a maximum speed of 3.7 mph (6 km/h), so it could easily be outrun and outmaneuvered ...

Beginning in World War II, ... in which British tanks will be built, ... medium and heavy tanks, self-propelled guns and tank recovery vehicles,” the News wrote in 1976.

There were lighter and quicker tanks operating in WWI, like the British-designed Medium Mark A Whippet (pictured), a 14-ton medium tank that used two four-cylinder 45-horsepower engines to achieve ...