Hussain Osman, a 27-year-old Briton of Ethiopian origin also known as Hamdi Issac, arrived in London aboard a private plane following a two-month legal battle against extradition from Italy.
  
Three alleged co-conspirators - suspected of trying to repeat the bombings on three London subway trains and a bus that killed 56 people on 7 July, including the bombers - were charged with attempted murder and conspiracy in August following their arrests in Britain.
  
Osman was to appear before magistrates on Friday at a special session convened at London's high-security Belmarsh Prison.
  
A private plane carrying Osman touched down at RAF Northolt, a military air base in northwest London, before 1:45pm (1245 GMT). 

Grave charges
  
A convoy of police vehicles took him to London's high-security Paddington Green police station where he was charged in connection with an attempt to set off a bomb on a subway train at Shepherd's Bush station, west London.
 
He is charged with attempting to murder passengers and to have unlawfully and maliciously made or had in his possession, or under his control, an explosive substance with intent to endanger life or cause serious injury to property.
  
He is also alleged to have conspired with others to cause explosions likely to endanger life or cause serious injury.
  
The plane left Rome's Ciampino airport shortly after midday local time (1000 GMT) after Osman was handed over to British police officers at the capital's Rebibbia prison.
  
Italy's highest appeals court upheld on 13 September a lower-court decision to extradite him at the request of British prosecutors.
  
Osman evaded heightened British security measures after the attacks and left London by train on 26 July, travelling to Rome via Paris and Milan.