POLICE officers were called to an "altercation" on a motorway bridge in Newport today where a group of Brexit supporters was holding a so-called Toot to Leave protest.

A member of the public allegedly confronted the protesters, threatened them with violence, and then tried to cut down their banner with a bladed object.

The group had unfurled a large banner and Union Jack flag over the M4 bridge at Junction 25 (Caerleon) and were encouraging the thousands of drivers passing below to sound their horns in support for leaving the European Union.

Among the protesters was David Simpson, who said the event had been passing by peacefully until a man parked on the bridge, got out of his car and made expletive-laden demands for the group to take their banner down.

Mr Simpson said the man physically threatened one of the protesters before producing from his pocket a sharp blade and trying to cut the banner free from the bridge.

Gwent Police later confirmed the bladed object had been a multi-tool.

Mr Simpson alleged that the man then turned to him and said "I'll do you if you stand still long enough".

The police arrived within minutes, Mr Simpson said, but the man had left the scene.

The protesters made no complaint to the police, but Mr Simpson said the incident had been unacceptable regardless of how people felt about Brexit.

"Our Toot to Leave campaign is peaceful," Mr Simpson said. "People have got to understand that whatever their political beliefs, there's no reason to get violent."

A spokesman for Gwent Police said "officers attended following the altercation, but no further action was required".