THE Iranian Government has continued to move aggressively to crush popular protests over the disputed presidential election, setting up a special court for demonstrators, detaining hundreds of independent and opposition journalists and activists, and sending police and militiamen onto the streets.The comprehensive crackdown left the centre of Tehran eerily quiet on Tuesday, given the huge demonstrations and clashes of recent days, in which at least 17 demonstrators have been killed.Arrests and intimidation left the opposition with no visible leadership, even amid mostly anonymous calls on the internet for more demonstrations and even a general strike.Stepping up its assertion of victory, the Government took the provocative step on Tuesday of announcing its intention to certify the re-election as president of Mahmoud Ahmadinejad and of having him sworn in by early August. The spokesman for the Guardian Council, the panel of clerics that oversees and certifies election results, flatly rejected all claims of electoral fraud, which sparked the most sustained challenge to the Government since the Islamic revolution in 1979.One of the defeated presidential candidates, Mohsen Rezai, has written to the Guardian Council withdrawing his complaints about the election, saying that the country's "political, social and security situation has entered a sensitive and decisive phase, which is more important than the election".However, there were growing signs of divisions among supporters of Mr Ahmadinejad. MPs, upset with the brutality of the official crackdown, summoned the ministers of justice, intelligence and the interior to a hearing.And while there was no talk of political compromise, the Supreme Leader, Ayatollah Ali Khamenei, agreed to extend by five days the actual certification of the election - a move that appeared largely symbolic.By Tuesday night, the Government's chokehold on the opposition appeared to have left it in disarray. The last confirmed public appearance of the reformist candidate Mir Hossein Mousavi was on Thursday, and he last issued a statement on Sunday. His website was not working well and his newspaper had been raided by the police and its staff of about 25 arrested.The question hanging over the opposition, a diverse collection of reformers, conservatives, clerics, students and members of the middle and working classes, was what, if anything, would take the extraordinary events of the last week forward.The Government continued to keep the opposition off balance, in part by detaining many people, including some with records of independence from the state but no connection with the protests.At least 55 journalists, intellectuals and former government officials have been held because of association with Mr Mousavi.In other developments, Britain has ordered the expulsion of two Iranian diplomats, in a tit-for-tat response to the expulsion of two British diplomats from Iran.Tehran told Britain it was throwing out two diplomats, who have not been named, for "activities incompatible with their diplomatic status" - a claim the British Prime Minister, Gordon Brown, described as "unjustified".On Friday, Ayatollah Khamenei singled out Britain as the "most evil" country.