Ian Lazenby saw the children as his own possessions - and if he could not have them, no one else could, Peter Galdwin, coroner for north Humberside and Scunthorpe, said.
Lazenby, 52, who was separated from his wife Sylvia, was found dead with the children in his Ford Granada in a country lane at Hibaldstow, south Humberside, last January. A hosepipe led from the car's exhaust through a window.
Mr Gladwin, recording a verdict that Lazenby took his own life by carbon-monoxide poisoning, added: 'His subsequent murder of the children was his final devastating punishment of his wife.'
The corner recorded that Princess Heidi, nine, Kelly, six, and Rachel, two, had been unlawfully killed. He said the children's murder and Lazenby's suicide were 'premeditated'.
The coroner heard how Lazenby, of Bordon, Hampshire, collected the children on the pretext of taking them on a day trip to the zoo but instead of returning them to their home in Horndean, Hampshire, he drove 250 miles to his mother's home in Grimsby.
Lazenby took the children to the seaside and to York and Lincoln, before driving to Hibaldstow, where the bodies were found on 26 January.
The coroner said that during the three-day inquest he had heard an 'abundance of evidence that Lazenby, who worked in a public house, was 'violent, selfish, aggressive and argumentative'.
'He thought a lot about suicide, though was equally capable of exercising emotional blackmail by his threats of suicide.
'Ian Lazenby had displayed a great deal of violence to his first wife and then to his second wife, Sylvia. This violent streak in him became evident when he assaulted his own father.
'Possibly, he would have benefited from psychiatric help years ago . . . However, such was his arrogance, I doubt very much if he would have accepted psychiatric treatment or advice.'
The coroner said that Lazenby's wife, Sylvia, could not have been expected to guess his intentions. 'Apart from other very serious defects in his character, Ian Lazenby was an accomplished liar,' he said. 'He viewed his children as his possessions. If he personally could not have them then no one else would.'
He said the children loved and trusted Lazenby and would have had no knowledge of death by carbon-monoxide poisoning.
The coroner went on: 'My first sympathy must go to these three innocent children on the threshold of their lives, only to have them terminated in this manner.
'Sympathy must also go to Sylvia, who has lost her three children because of this vindictive act of her husband. And I am thinking of the family in Grimsby and Sylvia's mother and stepfather.'
After the hearing, Mrs Lazenby, who has a three-month-old son, James, said she had not wanted her husband to 'get away with it' by the coroner saying that the balance of his mind was disturbed. She was pleased with the verdict.Reuse content