Iranian authorities say five out of the nine British embassy staff detained in Tehran have been released. State television says the four staff still in custody are being held for further questioning.Britain has demanded the immediate release of the workers, accused of involvement in the street demonstrations that followed the disputed June 12 presidential election. Yesterday the British Foreign Secretary David Miliband said his European Union colleagues had agreed on what he called a “strong, collective response” to any “harassment and intimidation” against EU missions. Iran has singled out Britain and the US with complaints that Western powers have interfered in its internal affairs and fomented unrest. London and Washington vigorously deny the allegations. Opposition groups in Iran have also said Iranians do not need to rely on the West to know when it is time to hold street demonstrations.