A tearful colleague of a young dad-to-be buried alive on a building site has apologised for fleeing in terror as the tragedy unfolded.

Labourer Gareth Lowery broke down as he told an inquest into Callum Osborne's death how he ran away when a trench collapsed on the young builder.

Desperate efforts were made to dig him out, but the 24-year-old, of City View, Canterbury, was pronounced dead at the scene in Swalecliffe.

The 33-year-old had been helping Callum lay a pipe, but was moved to another job on the Whitstable site after disagreeing with the way it was being done.

Mr Lowery said he went for a break after boss Wayne Cooper decided to take over.

Callum and Mr Cooper were digging in a narrow alleyway and building up spoil on both sides when the trench started to give way.

Mr Lowery told the inquest at the Guildhall in Sandwich: "Wayne started screaming for help.

"As soon as I realised what was happening I ran, I panicked. Wayne said 'the mud's collapsed on Callum'.

"He asked me to help and I couldn't. It was obvious what had happened. I ran to my van and I was just shaking."

Turning to Callum's relatives in the front row of the court at, Mr Lowery said: "I'm so sorry I ran away.

"As soon as I realised what was happening I ran, I panicked. He asked me to help and I couldn't. I ran to my van and I was just shaking..." - Gareth Lowery

"Callum's job was to guide the digger along the trench, making sure the floor was smooth and ready for laying.

Investigating officer PC Daniel Pearce said he noticed mud had been piled behind a wooden fence by the digger driven by Mr Cooper.

He said: "I could see a small digger perched on a mound leaning to one side. I could see the fence posts had split and a large quantity of soil pushed against it and it had collapsed."

Health and Safety Executive inspector Caroline Penwill said Cooper Services Ltd, the firm employing Callum, did not have an up to date HSE certificate.

She arrived at the scene three hours after the tragedy.

She said: "There was spoil banked up on each side. There were no supports and no barriers and Mr Cooper didn't have a risk assessment."

The inspector said the trench was about 1.9 metres deep. The officers could not measure exactly as it was likely there would be another collapse.

Earlier this week, coroner Roger Hatch heard the site had been described as "exceptionally bad" just hours before the tragedy.

The inquest, which started this week more than three years after the tragedy on April 7, 2011, is expected to continue into next week.