DRIVERS are threatening to withdraw evening bus services throughout the York area after a shotgun was fired through the windscreen of a city bus.

The attack marked a dramatic escalation in potentially lethal incidents that have been happening across the city on an almost daily basis.

The latest, and most terrifying, incident was aimed at a First bus travelling in Huntington Road on Saturday night.

Dave Bolton, a spokesman for the Transport and General Workers' Union, said: "There is absolutely no way we will run services in the evening if these attacks continue in any way, shape or form."

Last week, a police van was attacked with bricks as it escorted a bus through Danebury Drive, and services were targeted every night across the city.

The shotgun incident brought the city's public transport service to a standstill as drivers called an impromptu two-hour strike yesterday morning to demand a full-scale investigation.

The driver and two passengers escaped uninjured, despite the windscreen, the upstairs window and the glass cover of the destination panel being shattered at 10.50pm at the junction with Highthorn Road.

Brick attacks on city buses have become almost a daily occurrence, said the company's accident investigator, Roy Tanner.

"That's bad enough, but what happened this weekend is incredible," he added.

"It's amazing that nobody has been hurt when bricks are being thrown, but this is really going big league and somebody could have been very, very seriously hurt or killed.

"The drivers are understandably worried about their own safety and the safety of the passengers.

Paul Bell, First's operations manager, said: "Drivers are increasingly concerned to go out, but it is very difficult to try to do anything about it. The attacks are happening across the city at random and it's very difficult to predict where they'll be."

The company is meeting councillors and police chiefs this week to organise a combined effort against the attackers, he said.

Police officers interviewed the driver yesterday, and forensic experts were expected to study the vehicle today.

A police spokesman confirmed they believed a shotgun had been used.

He said: "Any use of a firearm is deeply concerning. To use it anywhere near a travelling vehicle is astonishing."

He said officers wanted to speak to a group of youths who were seen near the scene.

The two passengers, who had been sitting upstairs at the front of the bus, were dropped off by the driver. Police are urging them to make contact.

The First company recently withdrew a service in Haxby after bus windows were smashed four times in a week. Last year, the last bus of the night through Chapelfields was withdrawn because of attacks. It has not been resumed.

Anyone with information about the latest attack should contact the police on 01904 631321.

Updated: 11:18 Monday, March 18, 2002