John McGuinness won the Senior event

The rider, named by race organisers as Marc Ramsbotham, 34, who was from Wymondham, Norfolk, died instantly.

One spectator, Dean Adrian Jacob, 33, from Kidderminster, Worcs, was pronounced dead at the scene.

The second, Gregory John Kenzig, 52, from Queensland, Australia was taken to Noble's Hospital, but died a short time later. Two other people were injured.

Hilary Beryl Musson, 60, from Ballaugh, Isle of Man and Janice Ann Phillips, 50, from Ramsey, Isle of Man, were also involved in the incident.

Investigation ordered

Ms Phillips' condition is described as stable while Ms Musson's was reported to be critical in a critical condition.

Organisers have begun an investigation into the accident.

The Manx Motor Cycle Club Limited confirmed the deaths and the identity of the rider in separate statements on Friday.

The organisers of the event express their sympathy to the families and friends of those involved Organisers' statement

Mr Ramsbotham was described by the club as a married man who worked as an HGV driver and plant fitter.

It said it was the first time he had raced at the event.

"The club extends its sympathy to his wife, family and friends," a statement on the club's website said.

Mr Ramsbotham was involved in an incident at the 26th milestone on the Mountain course - known locally as Joey's.

"The coroner has been informed and an investigation into the circumstances of the accident is under way," a club spokesman said.

More than 200 people have been killed on the course since the first tourist trophy race in 1907.

The deaths overshadowed the centenary festival, which had been brought to a close by John McGuinness with victory in the Senior race - his 13th TT victory.