Six years after his ouster, Egypt's ex-President Hosni Mubarak has been released from detention after being cleared of inciting the killings of hundreds of protesters in 2011.

Mubarak, 88, on Friday left a military hospital in Cairo's southern suburb of Maadi where he had been held in custody and went to his home in the upscale Heliopolis district under heavy security.

His lawyer, Farid el-Deeb, told the Egyptian newspaper al-Masry al-Youm that he celebrated his release with breakfast his wife Suzanne and their two sons, Alaa and Gamal.

Mubarak was cleared for release earlier this month after the country's highest appeals court acquitted him of any involvement in the deaths of nearly 900 Egyptians during the 25 January - 11 February 2011 uprising.

He had been sentenced to life in 2012 but an appeals court dismissed the charges two years later.

Timothy Kaldas, a non-resident fellow at the Tahrir Institute for Middle East Policy, told Al Jazeera that it was unlikely "both now or any time in the foreseeable future that anyone will be prosecuted for the murders.

"Mubarak being in or out of prison doesn't change the fact that the military the took control in Egypt in 1952 continues to rule Egypt today.

"[Mubarak's] role in Egyptian politics is of limited consequence today, [but] there's a real sense of injustice that while many revolutionaries are in prison - he has walked free."

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The ouster of Mubarak, who ruled Egypt for 29 years, led to the country's first free election but the winner, Muslim Brotherhood leader Mohamed Morsi, was overthrown in a military coup in 2013.

Army chief Abdel Fattah el-Sisi has since waged a fierce crackdown on Morsi and the Muslim Brotherhood with human rights groups claiming as many as 60,000 political prisoners currently languish in Egypt's jails.

In contrast, Mubarak-era figures are slowly being cleared of charges and a series of laws curtailing political freedoms have raised fears among activists that the old leadership is regaining influence.

"As Hosni Mubarak goes free in Egypt, thousands of prisoners still languish in horrific prison conditions," Harriet McCulloch, a deputy director at human rights organisation Reprieve, told Al Jazeera.

"Many face the death penalty on charges relating to protests, in mass trials that make a mockery of due process," McCulloch added.

"Some were arrested as children - people like Irish citizen Ibrahim Halawa, who has suffered terrible abuses in jail. The Sisi government must now show that Egypt's justice system is worthy of the name and release Ibrahim, and the hundreds like him."

A former air force chief and vice president, Mubarak became president after fighters who had infiltrated the army shot dead president Anwar Sadat during a military parade in 1981.

Mubarak, then vice president, was metres away from Sadat during the attack and was shot in the hand. He was sworn in as president eight days later.