in 1825, clifford's tower and the waud house were purchased by the county of yorkshire at the cost of £8,800 (£665,000 at 2009 prices). the new prison buildings, designed by architects p. f. robinson and g. t. andrews, were constructed in a tudor gothic style, including a gatehouse 35 feet (11 metres) high and a radial prison block, protected by a long, high stone wall. the prison, considered to be the strongest such building in england, was built entirely of stone to be both secure and fireproof. dark grey gritstone was used in the construction to produce a forbidding appearance, although the prison itself was considered healthy and well ventilated.