Hugh Galashan, 62, was actually caught in a sting by an undercover police officer posing as the woman and the children did not exist.
He has now been jailed for four years at Bradford Crown Court after being previously found guilty of 13 counts of arranging or facilitating the commission of a child sexual offence.
The court heard how Galashan had arranged online between April 26 and May 19 of this year to travel to Sheffield with the intention of meeting up with and raping a four-year-old girl and a baby who, unknown to him, did not exist.
But when he arrived in Sheffield on May 19 he was arrested by officers from Bradford’s Police Online Investigation Team (POLIT).
During his trial, Galashan, of Fallowfield Gardens in Bierley, Bradford, tried to convince the jury that he had not intended to sexually abuse the children, and his intention was to have sex with their mother, whom he believed he was speaking to in his online interactions.
The jury were not persuaded by his argument and he was convicted unanimously on all counts.
Galashan served in the British Army as a vehicle mechanic from 1975 to 1994, reaching the rank of staff sergeant and being attached to several regiments including the Royal Irish Rangers, Royal Highland Fusiliers and the Tank Regiment.
West Yorkshire Police investigating officer PC Adam Flaxington said: “This was a particularly distressing case where Galashan brought with him sweets as gifts for the children as well as sexual items to facilitate the abuse of two children, the youngest of which he believed was only four months old.
“The extensive and strong collaboration between officers from our online investigation team and the Yorkshire and Humber Regional Organised Crime Unit ensured Galashan was brought to justice.”
Detective Inspector Marie Bulmer, from YHROCU, said: “This forms part of our continued priority to protect children from sexual exploitation from those who seek to do them harm. Law enforcement operates across the internet, and we will relentlessly seek to bring to justice individuals who use the web to facilitate the abuse of children.
“Reports of child sexual abuse should be made to your local police force via 101. All reports will be followed up, no matter when they occurred.
“Victims can talk in confidence to experienced Investigators and we can also help them access a range of other support services.”
“Anyone with concerns about internet use or behaviour towards children is also encouraged to seek advice and support.”