A plumber is to face trial accused of causing a gas explosion that obliterated a couple's home and buried them beneath rubble.

Craig Hall, 34, is said to have failed to properly install a boiler at Robin and Marion Cunningham's house in Callander, Perthshire.

As a consequence, it is alleged the boiler's supply pipe separated from the inlet pipe to which it should have been joined, allowing gas to escape.

Eight months after Hall carried out the work, the property was completely destroyed in a massive blast.

At 5.45 am on August 2, 2013 the escaped gas ignited, possibly when Mr Cunningham went to make his wife a cup of tea, resulting in an explosion that ripped through the property.

The couple were both trapped and had to be freed by fire-fighters.

Mr Cunningham, then 77, was taken by air ambulance to the Southern General Hospital in Glasgow where he was treated for a back injury and burns.

His wife, then 74, was taken to Glasgow Royal Infirmary with less serious injuries.

Nine nearby houses were evacuated and Stirling Council set up a rest centre in Callander as emergency services moved in to make the area safe.

Mr and Mrs Cunningham's home was almost completely demolished in the explosion and diggers were called in to clear the site.

At Stirling Sheriff Court on Tuesday Hall, of Tullibody, Clackmannanshire, pleaded not guilty to causing the blast by carrying out the installation of the boiler dangerously and otherwise than in accordance with appropriate standards.

He also denied an alternative charge, under the Health and Safety at Work Act, of failing to take reasonable care for Mr and Mrs Cunningham's safety as a result of his "acts or omissions".

Sheriff Christopher Shead set trial for August 2, with a pre-trial review on July 4.