HM Prison Portland is a male Adult/Young Offenders Institution, located in the village of The Grove on the Isle of Portland, in Dorset, England. Portland YOI prison is operated by Her Majesty's Prison Service. The prison was originally opened in 1848 as an adult convict establishment, before becoming a Borstal in 1921, and a YOI in 1988. In 2011 the prison's became an Adult/Young Offenders establishment.HistoryIn November 1848, Portland's prison was opened for the holding of adult convicts. The purpose of a prison on the island was largely for the use of convict labour, to help construct the breakwaters of Portland Harbour and its various defences. The first convicts, totaling 64, arrived aboard the HM Steamer Driver on 21 November 1848. A large array of nearby quarries were developed for convicts to work in. Once established, the Admiralty Quarries, as they were known, saw convict labour providing 10,000 tons of stone per week for use on the breakwaters. The conditions within both the prison and its quarries throughout the 19th-century would later help calls for penal reform in the UK, as many prisoners died while quarrying stone.From the moment of the prison's inception, the convicts became a tourist attraction. The village of The Grove had been developed directly due to the prison, and a number of homeowners decided to open cafes from the upstairs of their houses for tourists to watch the convicts at work. In 1855, a waterworks, known as Folly Pier Waterworks was built below the prison on the eastern coastline, to provide water to the prison.