Two senior United Nations officials have told the UK Government that national security concerns “must never be used as an excuse” to curtail press freedom.

The comments from Frank La Rue, the UN’s special rapporteur on freedom of opinion and expression, and Ben Emmerson, special rapporteur on human rights and counter-terrorism, came in the wake of the row over the detention of the partner of Guardian journalist Glenn Greeenwald last month.

David Miranda was held for nine hours at Heathrow Airport under Section 7 of the Terrorism Act and has since launched a legal bid attempting to stop British security services from inspecting data that was seized from him.