Police Scotland has paid £1m in compensation to the family of a woman who died after being left for three days in a crashed car on the M9 motorway.

The force has settled a compensation action taken by the family of Lamara Bell, 25, after they sued over its failure to respond to a call from a farmer who had spotted a crashed car lying off the hard shoulder in 2015.

When police finally arrived at the scene three days later, after a second call from the public, they found Bell in critical condition and her partner, John Yuill, 28, dead alongside her. She died in hospital four days later, leaving two children, aged 5 and 10. The Record newspaper has reported that the children, now in the care of grandparents, will be awarded £500,000 each.

The force has already admitted there were avoidable failures in its call-handling system which “materially contributed” to her death, and issued an unreserved apology. It was found guilty in September of corporate criminal liability.

The family’s lawyer, David Nellaney of Digby Brown, said they welcomed Police Scotland’s compensation payment but criticised the force for failing to settle the case at a far earlier stage.

“The Bell family has endured things very few people could ever comprehend but the patience, resilience and compassion they have shown at all times cannot be understated,” he said.

“It is unfortunate that Police Scotland did not admit its failings sooner as it might have spared them unnecessary distress, but at least we do now have a conclusion and the Bells can rightly focus on themselves and times ahead.”

In a statement, the Bell family said the settlement was the end of “chasing answers, recognition and justice for six years”.

They added: “Our pain and loss won’t stop just because the legal proceedings are over, but there is at least a sense of peace that comes with their conclusion. But that peace is fleeting because ultimately we are still without Lamara.

“We are without a daughter and sister and her children are without a mother – such an outcome cannot, and should not ever, go unheeded in a fair society and we are glad to finally have attained that which we sought.”

The deputy chief constable, Fiona Taylor, said: “Lamara Bell and John Yuill’s deaths were a tragedy and our thoughts remain with their children, families and friends.

“The chief constable has been very clear that Police Scotland would engage with any legal process which may take place. It would not be appropriate to comment further at this time.”