28-year-old Jason Marshall, from Greenwich, was arrested at Heathrow Airport on 15 February 2017 for the murder of Peter Fasoli.
Mr Fasoli, 58, died on 7 January 2013 after a fire at his flat on Rubens Road in Northolt.
The investigation into the death of Mr Fasoli only began in November 2014 after new evidence was passed to the Met Police by West Yorkshire Police. The fire was treated as unintentional until additional evidence was brought to officers from the Homicide and Major Crime Command.
The trial, which begins today, is due to last three weeks.