<span style="color: #222222;">An Iranian tanker seized by Gibraltar last month is preparing to set sail after being released, a senior Iranian shipping official said today.<br />''<br />'' The seizure of ship on July 4, with the help of British Royal Marines, triggered a sharp deterioration in relations between Tehran and London and the tit-for-tat detention by Iran of the British-flagged tanker Stena Impero.<br />''<br />'' The Grace 1 will be renamed and switch to the Iranian flag for its onward journey, the deputy head of Iran's Ports and Maritime Organisation, Jalil Eslami said.<br />''<br />'' Gibraltar's Supreme Court ordered the tanker released yesterday after the British overseas territory said it had received assurances from Iran that the Grace 1 would not head to any country subject to European Union sanctions. </span><br />