The fatal incident occurred just after noon on Thursday on the deck attached to the bridge’s north tower. It is understood that the worker died after he was hit by the boom of a spider crane.

The worker suffered severe blood loss, and was taken off site but could not be resuscitated.

A second man was involved in the accident and was also rushed to hospital however his injuries are not thought to be life-threatening.

He was taken by boat to the Hawes Pier at South Queensferry, where he was transferred onto an ambulance and taken to hospital.

Work on the crossing stopped for investigations to take place but workers returned to the bridge this morning for a safety briefing following the incident and are expected to continue construction.

Union leaders said the death on Workers’ Memorial Day was a poignant reminder of the dangers in the construction industry. The day sees workers across the world gather to remember those who have lost their lives as a result of injury at work or occupational diseases and commit to fight for safer and healthier workplaces.

Harry Frew, regional secretary for UCATT Scotland, said: “UCATT sends its sincere condolences to the family of the worker who has suffered this tragic accident. It is impossible to imagine how they must be feeling.

“UCATT will be doing everything it can to find out how and why this accident occurred and to ensure that similar fatalities are prevented in the future.”

Pat Rafferty, Unite’s Scottish secretary, added: “Once again, a loved one has gone to work and will not return home.

“We call on the Scottish Health and Safety Executive to thoroughly investigate what has happened here.”

Work on the new £1.4 billion crossing started in 2011 and the death is the first fatality at the site.

A total of 1200 people are currently working on the site, but more than 10,000 have been involved at various stages of the construction process.

A worker on the bridge, who asked not to be named, told STV News: “The safety record’s been really good. Everyone’s shattered.”

A Police Scotland spokesman said: “We are currently working alongside our partner agencies to investigate an incident on the Queensferry Crossing Bridge that resulted in a man sustaining fatal injuries.

“The call was received around 12.20pm on Thursday and sadly, the man was pronounced dead a short time later.

“Another man on the bridge also sustained minor injuries. Inquiries to establish the full circumstances surrounding this matter are ongoing.”

A spokesperson for the Queensferry Crossing project added: “We are deeply saddened to have to confirm there was an incident just before noon on April 28 on the Queensferry Crossing’s north tower in which a person has lost his life. One other person has been taken to hospital. All activity has been stopped at the north tower.

“Our thoughts are with the family and friends of our colleague and co-worker at this time.”

An investigation will be carried out by the Health and Safety Executive.

The 2.7km bridge is being built by the Forth Crossing Bridge Constructors (FCBC) consortium, comprising Hochtief, Dragados, American Bridge and Morrison Construction under a £790 million contract.

It is due for completion by the end of the year.