Two men have been jailed following the fatal tipper truck crash in Bath in 2015.
Company director Matthew Gordon was jailed for seven years and six months, while mechanic Peter Wood was jailed for five years and three months after being convicted for their involvement in the death of four people in Lansdown Lane in February 2015.
The pair were found guilty of manslaughter late last year, after the vehicle operated by firm Grittenham Haulage was found to have a catalogue of safety failings. Phillip Potter, who was at the wheel of the tipper truck when its brakes failed, was acquitted of all charges against him.
Gordon was also banned from being a company director for 12 years.
DCI Richard Ocone said: "Firstly, our thoughts remain with all those affected by this horrific incident.
"These sentences reflect the seriousness of the offences committed, bringing to a conclusion a complex 22-month investigation, which centred on the blatant disregard of a company in its duty of care to the public.
"As a company owner Matthew Gordon had no transport manager and effectively flouted every regulation, which had been put in place to ensure safety.
"His mechanic Peter Wood signed off vehicles as safe when they clearly were not.
"Detailed and complex investigations showed many of the faults on the vehicle were longstanding – highlighted by the fact that the brakes on the lorry at the time of the crash, were totally inadequate, having an overall efficiency of just 28 per cent.
"If there is just one single lesson to be learned from this sad and tragic incident, it is that company transport owners must adhere to a duty of care, which includes regular maintenance and servicing of all vehicles.
"The public needs complete reassurance that this work is undertaken regularly and remains a top priority for all companies.
"I would once again like to thank our partners in this investigation – the Crown Prosecution Service and the Driver and Vehicle Standards Agency – for their expert advice and support in what was an extremely complex and detailed investigation.
"Finally, I hope that the jailing today of both Matthew Gordon and Peter Wood helps to provide some form of closure on this particularly difficult and traumatic time for the family of those who died or suffered serious injuries following the dreadful incident on 9 February almost two years ago."
Alyson Harris, senior crown prosecutor for the CPS said: "Matthew Gordon and Peter Wood have been sentenced but we need to remember the devastation their gross negligence caused to innocent lives and their families as well as the deep impact this has had on the community at large, including the emergency services and all the passers-by who attended the scene many of whom were traumatised by what they saw.
"The Crown Prosecution Service worked with the Police and then with the barristers who presented the case for us for over 18 months in order to achieve this result and we hope that it will bring some sense of justice to all those hurt by this terrible collision."
However Gary Rae, campaigns director for Brake, the road safety charity, said: “Our thoughts are with all four families on what must have been yet another milestone, as they attempt to come to terms with life without their loved ones. This was a wholly preventable tragedy - a rogue operator running a lorry that was riddled with lethal faults. Their casual disregard for safety led to four deaths. The sentences passed are unduly lenient for the crimes committed.”