Sudan's last elected prime minister said on Tuesday he would run for president in April's elections, promising to settle the Darfur conflict.
Sadeq al-Mahdi was overthrown with the rest of his civilian government in a bloodless coup by Sudan's current President Omar Hassan al-Bashir in 1989.
"Now it is possible for the people to reinstate (the person) who they believe represents their interests ... represents their aspirations," he told reporters after handing in his nomination for the ballot.
"This is simply a return to normal because I have not been fired by the people. I have been fired by the guns," he said.
The head of the opposition Umma party is also a descendent of a visionary Islamic leader who fought the British in the nineteenth century.
Sudan is preparing for a complex set of presidential and legislative elections promised under a 2005 peace deal that ended more than two decades of civil war between north and south Sudan.
Umma and other opposition groups have complained of widespread fraud during voter registration and last year threatened to boycott the poll if democratic reforms were not pushed through.
Mahdi released a statement on Tuesday saying the elections should be delayed until November so that officials could have time to deal with all their concerns, but added he had decided to go ahead with his candidacy in the interests of the country.
"The announcement of an electoral boycott because of the flaws at this time would not serve the national interest," read the statement.
Mahdi, who leads the Ansar Islamic sect, was greeted by scores of chanting supporters as he registered his name at the Khartoum headquarters of Sudan's National Elections Commission.
"We think our programme is going to dismantle totalitarianism ... and create conditions for Sudan united on new principles or neighbourhood between two sisterly states," he told the crowd.
People from Sudan's oil-producing south have been promised a referendum on whether to become an independent country or stay united with north Sudan in January 2011.
He also said his party could resolve Sudan's separate western Darfur revolt, where rebels took up arms in early 2003 accusing central government of neglect.
The other major northern party which shared power with Mahdi in 1986, the Democratic Unionist Party (DUP), mostly followers of the relgion Khatmiyya sect, said it would formally register its presidential candidate on Wednesday.
Ending months of speculation that the DUP may back either President Omar Hassan al-Bashir or Mahdi, the party said their spokesman Hatim el-Sir would run for the presidency.
Even though DUP leader Mohamed Osman al-Merghani has lived in exile until late last year, the party is likely to attract many votes from its vast religious following who believe Merghani is descended from the Prophet Mohammad.