A London bus operator has apologised after a novice driver caused panic in Bounds Green by accidentally setting off the bus attack alarm system.

Just weeks after 13 people died on a bus targeted by a suicide bomber in central London, a 299 bus travelling along Brownlow Road towards Cockfosters emitted a loud siren sound accompanied by the recorded message "This bus is under attack. Please call 999."

Terrified motorists pulled off the road and along side-streets to avoid the vehicle, at around 3.45pm last Thursday, while pedestrians looked on in fear.

The driver of the car in front of the bus, who did not want to be named, said: "I couldn't believe it when the alarm went off I was terrified and wished the traffic would move faster.

"The panic was clear to see on people's faces, just a week after four people tried to bomb London's transport system."

He said he was even more astonished when it was triggered for a second time.

He added: "The bus company needs to sort its act out."

A police spokeswoman said it had not received any calls from the public concerning the incident in Brownlow Road.

Bus company First, the operator which runs the 299 route, this week apologised for the mistake. A spokesman said: "It was a new driver who pressed the wrong button in error.

"We are sorry to have caused any panic. It is unfortunate that it happened, especially at this time."

The terror attacks last month have led to hundreds of security alerts on the capital's Tube and bus network, and Transport for London (TfL) officials this week called on people not to leave bags unattended at any time.

A spokesman said: "At this time, it is irresponsible in the extreme for a minority of passengers to cause major disruptions through thoughtlessness.

"We are asking everyone travelling in the capital to help us by keeping hold of their possessions and getting rid of their litter sensibly."