An angry bus passenger threatened to kill a mother and her two-year-old son after he was told to stop swearing.

The mother was travelling with her two-year-old son on the free shuttle bus between Coronation Gardens and Shoreham Beach at 7.30pm on Wednesday June 5.

The woman told a fellow passenger, a heavily tattooed man in his 20s, who was shouting and swearing while on the phone not to swear in front of her son.

The man responded by threatening to punch her son and kill both of them.

Sergeant Simon Smith said: "I am appealing for any witnesses who were on the bus to come forward, and anyone who recognises the distinctive description of this man to get in touch.

“This is a nasty unprovoked attack where the victim was extremely vulnerable and alone with her small child.

“Other passengers on the bus helped the victim and we would like to speak to these people in particular.”

Anyone with information is asked to contact police on 101 quoting serial 1512 of 5/6.