Two workmates fought to save the life of a landscape gardener who was buried alive when the trench he was digging collapsed.

Using their hands and a shovel, the pair desperately tried to dig 42-year-old Karl Achermann from the heavy soil which fell from the walls of a nine foot trench, an inquest heard.

Despite the efforts of labourer Robert Austin and builder Michael Scott, Mr Achermann died from asphyxiation caused by the pressure on his chest.

The inquest jury at Lewes Magistrates Court heard on Friday that Mr Achermann had been digging the channel to form an ornamental lake.

Mr Austin explained they had been building the large pond in the ten-acre garden at Greenbanks, Shepherds Hill, Buxted, near Crowborough on May 11 last year.

He said: "Karl jumped down to the bottom of the trench. I saw a tremor in the wall and shouted for him to get out but the soil collapsed. He could not run.

"I shouted and then started to dig at the soil."

Michael Scott, of Manor Close, Horam, said: "I was working on stonework about 100 metres away. I heard a shout from Robert and rushed over to the trench. I could not see Karl at all. Then I saw his hand. We scrabbled away at the mud. We started digging like mad.

"We found his wrist and then his arm which must have been raised. We followed his arm down but could not find his head. There was an immense amount of earth. He was about eight or nine feet down. We were digging and throwing the soil over our shoulders. We managed to get to his chest."

By the time emergency services could take over the rescue effort, Mr Achermann was dead.

The men had been using an excavator to dig the trench before lining it with strong waterproof rubber sheeting to form the sides of the lake.

They had completed half of the circular ditch by 2pm and had been putting the soil from the mechanical digger above it.

Mr Achermann, of Barnsden Farm, Duddleswell, near Crowborough, jumped into the hole to secure the sheeting.

The inquest heard the weight of the soil above the trench could have contributed to the earth falling on top of him.

Landscape architect Christopher Blandford is the owner of the estate on which the lake was being built.

He told the jury he had warned Mr Achermann about the danger of going into the trench and produced details of the work plan which advised him not to do so.

He said: "I was asked to make clear the risks of going down. He agreed there was a risk."

Dennis Bodger, of the Health and Safety Executive, said the way the lake was being constructed constituted an "unsafe practice".

East Sussex coroner Alan Craze said: "People will assume a collapse is not going to happen.

"They should realise it can happen and at some time, as in this case, it will."

The jury returned a verdict of death by misadventure on the direction of the coroner.