David Miliband, the Foreign Secretary of UK, urged Iranian authorities to overturn a ''harsh'' four-year sentence reportedly handed down to a British embassy employee for spying. Hossein Rassam, an Iranian who worked as the embassy's chief political analyst, was arrested in June as the authorities in Tehran clamped down on massive street protests following the disputed presidential election. His arrest came as relations between Britain and Iran plunged to a new low, with Tehran accusing the UK of fomenting opposition demonstrations. Mr Miliband said reports from Iran that Mr Rassam, 44, had been sentenced to four years in jail were ''deeply concerning''. Iran's ambassador in London was summoned to the Foreign Office to explain the action. In a statement issued by the Foreign Office in London, Mr Miliband said: ''Such a decision is wholly unjustified and represents further harassment of embassy staff for going about their normal and legitimate duties. ''Our ambassador in Tehran has spoken to the deputy foreign minister to express our concerns and our acting permanent under secretary has called in the Iranian ambassador in London. ''We understand the sentence can be appealed. I urge the authorities to conduct this quickly and overturn this harsh sentence. ''We are in close touch with EU and other international partners, who continue to show solidarity in the face of this unacceptable Iranian action. This will be seen as an attack against the entire diplomatic community in Iran and important principles are at stake.''