The rights organisation has carried out more than 200 interviews since the beginning of anti-government demonstrations in the country in March last year. Accounts from former detainees and defectors have identified the locations, agencies responsible, torture methods used and, in many cases, the commanders in charge of 27 detention facilities run by Syrian intelligence agencies.

Human Rights Watch said the systematic patterns of ill-treatment and torture it had documented clearly pointed to a "state policy of torture and ill-treatment", which constituted "a crime against humanity".

Mr Hague said the UK would work with EU partners to impose sanctions on those responsible to help bring an end to the violence.

The report, Torture Archipelago: Arbitrary Arrests, Torture and Enforced Disappearances in Syria's Underground Prisons since March 2011, includes maps locating detention centres, video accounts from former detainees and sketches of torture techniques described by people who witnessed or experienced torture in the facilities.

Interrogators, guards, and officers used a broad range of torture methods, including prolonged beatings, often with objects such as batons and cables, holding the detainees in painful stress positions for prolonged periods of time, the use of electricity, burning with acid, sexual assault and humiliation, the pulling of fingernails, and mock execution.

Human Rights Watch documented more than 20 distinct torture methods used by the security and intelligence services. While most of the torture victims interviewed by Human Rights Watch were young men between 18 and 35, the victims interviewed also included children, women, and the elderly.

Human Rights Watch called on the United Nations Security Council to refer the situation in Syria to the International Criminal Court (ICC) and to adopt targeted sanctions against officials credibly implicated in the abuses.

Commenting on the report, Mr Hague said: "This Human Rights Watch report should act as a clear warning. There should be no impunity or hiding place for those committing these crimes. Those responsible for systematic and widespread human rights violations should not delude themselves: we and our international partners will do everything we can to ensure that they will face justice.

"Where we have evidence of individuals' responsibility for acts of violence and repression, the UK will work with EU partners to impose sanctions on them. We will continue to focus attention on what is happening in Syria and work to bring an end to the violence."

Source: dailystar.co.uk