A furious mum says her autistic son was left shaken after he was allegedly told he would be stabbed because his girlfriend was "talking too loud".

The boy, 15, was waiting at the bus stop in Station Square, Petts Wood, when an older teenager approached with a friend yesterday afternoon at around 3.15pm.

"He came up and told him to shut his girlfriend up," the mum, who will remain anonymous, told News Shopper.

Her son, who was on his way home from a special needs school, stayed quiet in the hopes of being left alone.

Despite not reacting, the older teenager continued to harass the pair.

"He then turned and said 'I’m going to stab you'," the parent added.

At one point he is said to have phoned his sister to tell her to come down and stab the boy.

The 273 bus arrived and the teenager apparently "kicked off" when the driver refused to let him on without a ticket.

According to the mother, the aggressive teenager was given an orange ticket by the driver stating that he could pay the fee at a later time.

The petrified boy was texting his mum while on the bus explaining what was happening.

"He was shouting and making him comfortable," she said. "I was nervous and told him if he got too scared to get off the bus and contact me."

READ: Suspect 'threatens to stab' someone in Orpington before police dog intervenes

The family live in St Paul’s Cray and police have been contacted who are investigating.

According to the teenager, the person threatening him was "bragging that he was 18" to his pal.

He also said he was black, around 5’6 tall and wore a green puffer style camouflage jacket.

The mother said knife crime was getting "too close to home" and believes punishments are not severe enough.

She cited a News Shopper story about a boy who was stabbed in Orpington last week.

READ: Two men arrested following Orpington stabbing have been released under investigation

"It could be fatal and what happens if the next kid dies?" she asked. "Will it be a slap on the wrist?"

The mum will be picking her son up from school by car from now until a solution is found.

A spokesman for TfL told News Shopper an orange slip can be given to people without a valid ticket or card.

He said it is specifically allocated to "vulnerable or distressed passengers" and typically includes those who are young or old.

Anyone with learning disabilities is also eligible and the slip allows you to pay at a later date.

UPDATE

Siwan Hayward, Director of Compliance, Policing and On-Street Operations at TfL, said: “We’re very sorry that this young man had such a distressing experience as this type of behaviour is completely unacceptable.

"All of our customers have the right to travel without fear of verbal or physical assault and we are working closely with the police to make travel safe for everyone.

"We’re supporting the police, who are carrying out a full investigation, and encourage anyone who experiences or witnesses this type of behaviour to report it."