A demolition site manager was given a suspended prison sentence today (Wednesday) after he was found guilty of health and safety failings which led to the death of a young labourer.

Robert Shore was just 20 when he was struck by a large lump of concrete that fell out of the bucket of an excavator and hit him on his head.

He died from the blow on the site at Smallford, near St Albans.

His death occurred on the morning of July 6 2011 and later an inquest ruled his death to be accidental.

But Health and Safety investigators found site manager Christopher Langton had failed that morning to take adequate steps to ensure the safety of Mr Shore, who was new to the job and inexperienced in working on demolition sites.

Mr Langton who, until the accident had an exemplorary record for site safety, had been operating the excavator that morning when the lump of concrete fell from the bucket and struck Mr Shore, who lived in Mimms Hall Road, Potters Bar.

But the young labourer shouldn't have been anywhere near the machine and Mr Langton should have taken steps to make sure he was in a safety area behind a barrier where he was at a safe distance from the excavator's arm.

Today Mr Langton, 49, a married father of two of Cadmore in Cheshunt, appeared for sentence at St Albans crown court.

He had been found guilty last week at the end of a trial where he had pleaded not guilty to an offence of Failing to Discharge a Duty to which he was subject to by virtue of Section 7 of the health and Safety at Work Act 1974.

The charge stated that he had failed to ensure the young man had remained behind a pedestrian segregation barrier while he was operating a Hitachi excavator on a rubble heap at the former British Telecom Research site in Oaklands Lane, Smallford.

Passing sentence on Mr Langton, trial Judge Stephen Warner told him: "You will have to live with the knowledge that it was your actions which caused his untimely death."

The judge said the jury at his trial had rejected the account he had given that he had instructed the young labourer to stay behind a barrier in a "safe zone" while he had operated the machine.

The judge said he had concluded that Mr Langton might not have known where Mr Shore was at the time he was struck by the concrete.

But he said he ought to have known.

During the trial, the court was told how, during the summer of 2011, work was underway on the former British Telecom research site at Oakwood Lane in Smallford to demolish a number of buildings on the site.

The defendant was the site manager.

The first phase in the work had been a "soft strip" of the buildings, which involved the removal of fixtures and fittings and service pipes and cables.

The next phase, which was underway at the time of the accident, concerned the actual demolition of the buildings and, for this, 360 degree tracked excavators were being used.

Mr Langton was skilled at operating the Hitachi excavator with its arm and bucket.

The jury was told this second phase required less people on the site.

As a result, only Mr Langton was working there along with another excavator driver and 20 year old Mr Shore, who was a labourer.

Prosecutor Mr Craig Rush said on the morning of July 6 Mr Langton was operating the excavator on top of a pile of rubble and debris that was to be converted into hardcore.

Mr Rush said it was about 10.15am and when he "slewed"  the arm of the excavator with its bucket on the end which contained a quantity of rubble.

As he slewed the arm, he noticed Mr Shore working close by.

As a result, he stopped the movement of the excavator's arm which caused a large lump of concrete to fall out of the bucket and hit Mr Shore on the head which killed him.

The prosecutor said "He didn't mean to kill Robert Shore, it was a dreadful accident but the prosecution say it was completely preventable. He failed to take measures he knew he should have taken and were required."

Mr Rush said the defendant had failed to take reasonable care of Mr Shore.

He had failed to fence off the area where he was working with the excavator and, as a site manager, he knew it should have been done.

The jury heard during the trial that Mr Shore was on the rubble pile to pull out scrap metal, a job that had been given to him by Mr Langton and which placed him in a "highly dangerous position."

The court was told the defendant had previously paid Mr Shore £20 for scrap metal he had pulled from the rubble.

On another occasion Mr Shore had received between £60 and £80 from the defendant.

Despite Mr Langton's good safety record on demolition sites over the years, the trial heard how, on the morning of his death, the young labourer had been warned he was too close to the arm of the excavator.

The judge said he accepted Mr Langton was "very conscious" of what he'd done.

Before he was sentenced today, the court was told Mr Langton was deeply remorseful for what had happened on July 6 2011.

Judge Warner was told the tragedy had taken a "terrible toll" on Langton, changing him from someone who before the accident had been cheerful to a man who was negative and withdrawn.

Mr Langton was described in court today as a man who had taken pride in working hard for his family.

Judge Warner sentenced him to five months imprisonment, which he suspended for 18 months.

In addition, he was told he would have to pay £3500 towards the cost of the prosecution.