Adrian Archibald swept the boards in four classes during practice

William Dunlop will miss Saturday's Ulster Grand Prix after suffering a shoulder injury in Thursday's practice session.

The 19-year-old, who had been aiming to compete in the event for the first time, came off his bike at the Irwin's bungalow section of the Dundrod circuit.

Thursday's second qualifying session had to be halted for a time after the incident.

His father Robert went on to top the 125cc qualifying with a fastest lap of 109.33mph.

Pre-event favourite Adrian Archibald dominated Thursday's qualifying sessions.

The Ballymoney man was fastest in four classes.

The TAS Suzuki rider's best lap came in the Superbike class when he was timed at 126.979mph which left him ahead of Richard Britton and Ian Lougher.

Archibald set an unofficial lap record of 123.243 in the Supersport 600 class while he was also fastest in both the Production races.

Dunlop sustained a suspected broken shoulder in the accident

His team-mate Bruce Anstey was fourth quickest in the Supersport 600 class.

The Kiwi, who won his first Isle of Man TT in June, has been called up to the all-conqering Northern Ireland-based road race outfit for the annual spectacular on the Dundrod circuit.

Archibald took a brace of wins in the Formula One and Senior events at the TT and was quick dedicate his successes to team-mate David Jefferies who was killed in practice for the Island races.

The Ballymoney man went on to record further victories at the Dundrod 150 national road races, setting a new absolute lap record at over 128mph for the County Antrim course.

Anstey has been making his mark too, winning the Junior 600 TT and beating Archibald in the same class at the Dundrod races a week later.

It was these performances which prompted TAS team manager Phillip Neill to secure his services.

The pair will not have it all their own way as Welshmen Ian Lougher and Jason Griffiths, Scot Iain Duffus and Irish riders Ryan Farquhar and Richard Britton all have realistic hopes of winning.

Lougher, a treble winner last year, will be aboard a Mark Johns Suzuki in the two Superbike races and a Manton Racing Honda in the 600 event.

Bruce Anstey won the Junior 600 TT in the Isle of Man

Griffiths is the official Yamaha GB entry, Duffus is part of the ETI Racing stable and Farquhar competes as part of the McAdoo Racing Team.

Another rider whose claims cannot be discounted is New Zealander Shaun Harris, a double winner at the TT in June.

This time the 39-year-old will campaign Suzukis for Ulster businessman Chris Dowd.

The 125cc races are also set to be highly competitive with Robert Dunlop, Lougher, Darran Lindsay, Chris Palmer and Paul Robinson all on the start grid.

A record prize fund of �38,000 is on offer this year for the seven-race programme.

The full list of races reads -

Production 1000 race (7 laps)

Production 600 race (6 laps)

125cc/Open 400cc race (5 laps)

UGP Superbike race (8 laps)

Supersport 600 race (7 laps)

Past Classic Forgotten Era race (5 laps)

Open Superbike Race (7 laps).