The brother of the Manchester Arena attacker, Salman Abedi, has been extradited from Libya to the UK to face multiple murder charges over his alleged role in the attack.

Hashem Abedi, 22, landed at an unspecified London airport on Wednesday, escorted by British police officers.

He has been charged with the murder of 22 people, the attempted murder of others who were injured, and conspiracy to cause an explosion. He remains in police custody in London and will appear at Westminster magistrates court.

Abedi was arrested in Libya shortly after his older brother carried out the suicide bombing as thousands of pop music fans left an Ariana Grande concert on 22 May 2017. Counter-terrorism officers had been granted a warrant for Hashem’s arrest but spent years negotiating his extradition with Libyan authorities.

The chief constable of Greater Manchester police, Ian Hopkins, said: “Our thoughts have been with the families of those who lost loved ones and the hundreds who are struggling with serious physical injuries and deep psychological effects.

“They have always been central to our investigation and will continue to be so at all times.”

Hopkins said Hashem Abedi was handed over by Libyan authorities to British police officers on Wednesday morning. “They escorted him on the flight back and he landed in the UK a short while ago,” he said.

Families of the victims and survivors were the first to be informed. Elkan Abrahamson, a solicitor representing some of the families affected by the terror attack, said: “The families have consistently been concerned about the security failings during the Manchester terror attack and they want any criminal proceedings against Hashem Abedi to conclude quickly and in time for the public inquiry next year.”

The time taken to return Abedi to the UK has meant the inquests into the deaths were delayed, with family members of the victims told that the full hearings were not likely to begin until April 2020 at the earliest.

The former British ambassador to Libya Peter Millett, who began Hashem Abedi’s extradition process two years ago while still in office, welcomed news of his arrival in the UK.

“I handed over the extradition documents in October 2017 to the Libyan attorney general. It has been a long drawn-out process, because of the complexities of extradition law in the UK and Libya. It was important to be scrupulous,” he said.

The home secretary, Sajid Javid, said the extradition was an important step forward in the investigation into the attack. “It’s important we now let the law take its full course,” he said. “My thoughts remain with the victims and their families who have endured so much. I would also like to pay tribute to the continued efforts of the dedicated police officers and all others who have worked tirelessly on this case.”

Abedi had been held since his arrest in May 2017 by Rada, the most powerful of Tripoli’s militias, at its base at Mitiga airport. Rada is allied to the UN-backed Tripoli government, and has won some support in the city for its campaigns against Islamic State and the city’s narcotics gangs.

But it caused controversy in 2017 when it arrested 140 participants of a comic book convention, saying it was investigating them for satanism and pornography.

The jail that held Abedi, inside the airport, holds dozens of terror suspects and gunmen, and has twice this year been attacked by rival militias trying to free members being held there.

The UN-backed Tripoli government is keen to garner western support in its battle against the eastern warlord Khalifa Haftar, who has been besieging the capital since April in fighting that has cost more than 1,000 lives.

One of the problems confronting the extradition process was that it was based on a treaty signed during the Muammar Gaddafi era, which does not allow Libya to extradite its own nationals to the UK. One western source said Abedi had entered Libya on a British passport and Libya’s justice officials had eventually decided he could be regarded as British and extradited within the terms of the treaty.

Since Britain evacuated its Libya embassy when fighting erupted in Tripoli in 2014, diplomats have also had to shuttle in and out of the city for negotiations with Libyan officials, causing further problems.

Detectives know the two brothers travelled together to Libya from the UK in April 2017, with Hashem Abedi remaining in Libya, the country of their parents’ birth. At the end of April, Salman, 22, returned to Manchester to carry out the atrocity, buying the components in local shops and assembling his bomb in a rented city-centre flat.

Both brothers were born in Manchester and went to school in the city.

No request has been made to extradite the brothers’ father, Ramadan Abedi, who was reportedly arrested shortly after his son.

Ramadan Abedi and the brothers’ mother, Samia Tabbal, fled to the UK as dissidents to escape Gaddafi. After settling first in London, they moved to Manchester, the home of the UK’s biggest Libyan community.

They returned to their homeland in 2011. That year, Ramadan Abedi fought against the Gaddafi regime with the Libyan Islamic Fighting Group during the Libyan revolution.