No-one has been arrested in connection with the assault
A £10,000 reward has been offered for details leading to the conviction of a passenger who broke a bus driver's arm.
The woman with a pushchair appeared to ask the female bus driver directions before attacking her and throwing her from the bus in Haringey, north London.
The driver also suffered a dislocated shoulder and facial injuries in the attack last year.
Crimestoppers said the offender, who carried out the assault in front of a child, was "utterly despicable".
'No stone unturned'
The unprovoked attack took place on the 221 bus route at the junction of Haringey's West Green Road and Turnpike Lane on 31 October 2008.
No-one has been arrested in connection with the assault.
Charity Crimestoppers and bus operator Arriva London offered the joint reward of up to £10,000 for information leading to the woman's arrest and conviction.
Ch Supt Joe Royle said: "People who think they can threaten and assault frontline staff and get away with it are wrong.
"We are determined that all offenders of bus violence are brought to justice and we will leave no stone unturned in our endeavour to do so."