Alipurduar: A vagrant believed to be mentally unstable drove away a government bus in Alipurduar for about 200 metres as the driver got down to have tea but left the keys behind on Thursday.

The residents of Falakata ran for their lives and the passengers inside the NBSTC bus screamed for help as the vehicle zigzagged through the town's main road.

The bus was eventually brought to a halt after another driver sensed something wrong and parked his vehicle obliquely to force Santosh Mahanta alias Raju, the vagrant, to slam the brakes.

Around 8am, the NBSTC bus, which was headed to Malda from Dinhata, reached the depot in Falakata. Most of the government buses moving through Falakata stop at the depot for 10-15 minutes for a refreshment break.

As the bus driver got down to sip tea, Santosh got into the driver's seat and pressed the ignition. He then drove the bus out of the depot and moved through the town.

Those who had got off the vehicle started running behind it frantically, along with the driver and other staff of NBSTC posted at the depot.

"I kept shouting at the top of my voice. But the person, instead of stopping the bus, accelerated," said Ratna Debnath, a passenger.

Santosh, however, was forced to slam the brakes when the driver of another bus parked his vehicle in a way that left little space for the vagrant to move.

The bus was taken back to the NBSTC depot and police were informed.

Police sources said Santosh, who was arrested, said it was his dream to drive an NBSTC bus. "He is humming songs in the lock-up," a source said.

"We have started a thorough investigation. If Najrul Mian, the driver, is found guilty, action will be taken against him," said Subal Chandra Roy, the MD of NBSTC.