Iran has failed to improve its record on human rights despite the government signalling a change in its approach, a report has found.
The Foreign Office said "serious" concerns remain over the lack of religious freedoms in the state and there is continued intimidation and censorship of journalists.
Relations with Tehran have begun to thaw since Hassan Rouhani was elected president last June. He has made moves to improve relations with the international community and work today began to curb uranium enrichment in the state under a deal reached in November.
Under the terms of the agreement, Iran agreed to halt progress on key elements of the nuclear programme in exchange for modest relief from certain economic sanctions.
Since president Rouhani took power the Iranian government has also made "positive public statements" on civil rights issues but there has been "no sign of institutional change", according to the Foreign Office.
Its report states: " There was no substantive improvement in the human rights situation in Iran between October and December 2013. The Iranian government continued to make positive public statements on civil rights issues, but there has been no sign of institutional change to improve the human rights situation, including for minority religious and ethnic groups, journalists and human rights defenders, prisoners and women.
" On November 26, in line with promises made during his election campaign, President Rouhani released a draft charter of citizens' rights," it adds. "Although this is a welcome exercise, without changes to the law or the approach taken by the judiciary and security forces, there is unlikely to be any real change."