Two homeowners were also severley injured in the blast after Alex Irvine was hired by John and Emily Reid to cut out a kitchen worktop and install a new free-standing gas cooker in Kirklands, Renfrew on March 31 2009.

Irvine was not competent to do the work and was not registered with Gas Safe Register.

Paisley Sheriff Court heard that Irvine told the homeowners he was not qualified but that he could still do it for a £60 fee.

After removing the kitchen unit and worktop, Irvine cut a copper pipe to remove an old gas hob, cleaned the end of the cut piece and attached a flexible, rubber hose.

The other end of the hose was attached to the new cooker before it was pushed back against the wall.

But one night while Reid was investigating a mysterious noise from the oven he moved it away from the wall which caused a massive explosion when he is believed to have caught the ignition switch with his thumb.

Both he and his wife were injured as the gas ignited, suffering burns to their face, hands, arms and neck before fleeing the property.

Reid underwent a skin graft on his right hand and Mrs Reid’s eyebrows and eyelashes have still not grown back.

The explosion also caused extensive damage to their home and three other properties. Three of the houses were so badly damaged they had to be demolished and rebuilt.

An HSE investigation found the hose was trapped between the cooker, the floor and side unit so it could become kinked when it was pushed against the wall.

Tests revealed that the hose had split at a middle point in the bend of the hose where it had been trapped, on both the inner steel winding and the outer rubber sheath coating. This would have allowed unburnt gas to enter the property.

Irvine, 44, of Paisley, Renfrewshire, was sentenced to 300 hours of community service after pleading guilty to safety breaches.

After sentencing, HSE Inspector Russell Berry said: “In carrying out this work while not registered and competent to do so, Mr Irvine put those living in this property and those nearby at risk.

“Thankfully Mr and Mrs Reid escaped with their lives, but were badly injured and four properties seriously damaged as a result of the explosion which was a direct result of the unsafe condition that the gas cooker was left in.

“Any business or sole trader who carries out work on any domestic or commercial gas appliances without being on the Gas Safe Register is breaking the law and potentially putting lives at risk.”