Hassan Turabi is coy about the connection between his National Islamic Front and General al-Bashir's Revolutionary Command Council. The NIF is formally disbanded, and Mr Turabi denies any role in government. Yet most of the RCC are at least sympathetic to his party, whose members have been insinuating themselves into every area of public life.
They have moved in two directions. They have set up parallel institutions to the existing state structures. The Popular Defence Force - in which every government employee and student must do four weeks basic drill, weapons training and religious indoctrination - is to counterbalance the army. Another police force has been set up beside the existing one, and other security organs have found a place alongside the established security apparatus.
At the same time, the NIF has been behind purges of the civil service, the army and the universities to weed out those not entirely in accord with its ideology. Career diplomats have been replaced by more politically correct zealots, often barely qualified.
Last week 149 army officers were summarily retired, according to human rights activisits working underground. Since 1989 some 11,000 army personnel have been removed, including 1,600 officers. Basic freedoms have been curtailed. The press is government-controlled, political parties are prohibited and trades unions have been replaced by ones compliant to the regime.
In the past six weeks, the government has made a determined drive to undermine the support of the Ansar religious order headed by the man deposed as prime minister by the military coup, Sadiq al-Mahdi, whose great-grandfather, Mohamed Ahmad al-Mahdi, founded the order. Dozens of senior local officials of his Umma party have been detained.
The confrontation with the government began on 25 March, after Mr Mahdi used the traditional sermon preached at the end of the Ramadan fast to call for a return to multi-party democracy in Sudan. Ten days later, just as he was about to meet two visting British MPs, he was briefly detained. Before this week's Eid feast, the authorities took no chances. Last week they announced the nationalisation of his ancestor's shrine, the Khalifa's Tomb, declaring it a national monument that should not be the focus of any one sect.
Mr Turabi explained that the old sects - the Ansar and the Khatmeyya sect of the Mirghany family that found expression in the now banned Democratic Unionist Party, most of whose leaders are now in exile - were obstacles to the establishment of true democracy in Sudan.
'Those who took power in Sudan say they . . . will not remain a military government,' he said. 'They will democratise the country and they say that the resort to party democracy is not a return to democracy, substantial democracy, but it just means sectarian leaders, dictatorship, because people just vote for a sectarian leader irrespective of his programme or conduct. They vote for his great-grandfather, they don't vote for Sadiq, they vote for the Mahdi.'
The NIF takes bits from the Libyan model, from Western democratic practice and Islamic ideas. The organisation enjoys more support than some of its critics would credit it with. Yet for all the talk of popular participation, in practice the government's policy has been simply to maintain and increase control through fear backed up by detention of political dissidents.
Mr Turabi sees international criticism of Sudan's human rights record as dictated by anti-Islamic sentiment. In December, the United Nation's General Assembly, with massive support from Arab and African countries, passed a resolution condemning Sudan's human's rights record, increasing its international isolation.
Mr Turabi expressed indignation that other countries, such as Egypt and Saudi Arabia, had committed far worse human rights abuses than Sudan. Yet most of the criticism came from other Muslims, either states in the Islamic world or Muslims in Sudan who do not share the NIF's interpretation of Islam. Some of the criticism has been exaggerated, and some of the more extreme Islamic punishments listed in the penal code have not been applied.
Sudan is the largest and one of the most culturally diverse countries in Africa. Even in the Arabic-speaking, Muslim north, which accounts for 70 per cent of the population, Islam is practised in many different ways.
Yet all the Muslim groups, in some way or other, would like greater Islamisation of the country. Where they differ is the extent to which the non-Muslim minority should be subjected to the Islamic order.
The hardline Muslim Brothers, more pan-Islamic than the government, regard Khartoum's attitude towards women and the south as too liberal.
Mr Mahdi has other ideological and religious differences with the current regime. 'We think that Islamic assertion is a general, legitimate phenomenon in the Muslim world,' he said. 'However it is totally at odds with dictatorial regimes. Islam should be clearly identified with the popular will, human rights and representative and accountable government.'