A former stock trader who drunkenly robbed Sydney banks more than four decades ago has been sentenced to three-and-a-half years in jail.

Ross McCarty, now 71, admitted to police he had a double life in which he would “get boozed at lunch time” for the hold ups in 1977 and 1978.

Using a water pistol and disguises including fake moustaches and sunglasses, McCarty wrote his demands for cash on withdrawal slips handed to tellers.

He wasn’t arrested until 2018 when the case was reopened and fingerprint analysis on the notes turned up a match in the police database.

On Friday, District Court Judge Sarah Huggett said McCarty committed the crimes as an “intelligent and educated” man in his late 20s, with both planning and purpose.

“They were deliberate, intended and motivated by financial gain.”

She sentenced McCarty to a total term of three-and-a-half years with a non-parole period of one year and nine months.

McCarty pleaded guilty to four robberies and another four hold ups were taken into account for the sentence.

His targets included ANZ, Commercial, the Bank of NSW, National Bank and the Rural Bank, and he would usually get away with $1000 or $2000 at a time.

Last week, McCarty read a letter addressed to the victims during a sentence hearing, apologising for the “terror inflicted” on them.

“My circumstances at the time made it easy to delude myself into thinking my appalling actions were justified,” he said.

“I wrongly thought that being polite and using words like ‘please’ and ‘thank you’ would let you know that I didn’t mean harm.”

McCarty owed significant debts to illegal gambling clubs in Sydney at the time and when he failed to pay up, thugs visited his office, threatened him with violence and warned him they knew where his wife lived.

“While his gambling may well explain his offending, his moral culpability is not reduced to any quantifiable extent by his gambling or alcohol use,” Judge Huggett said on Friday.

The court heard McCarty’s gambling went hand in hand with alcoholism, but he had not had a drink or placed a bet in more than 30 years.

McCarty was diagnosed with adult Attention Deficit Hyperactivity Disorder at the age of 60.

“The effect of medication was immediate and transformative, it stops the madness and activity, and enables some focus,” he said last week.

McCarty also told the court that his wife of five decades knew nothing of his offending until he was charged and that she was “another victim”.

“My greatest concern about returning to prison is the situation with my wife and her physical and mental wellbeing, as she doesn’t have a huge support network,” he said.

McCarty works as a project manager and his boss has offered to re-hire him after any jail term.

Court documents revealed McCarty told police his AA sponsor had been the only other person aware of his offending – and that person took it with them to the grave.

McCarty will be eligible for parole in March 2022.

-ABC