Some 282 cases have been referred to the police and 99 volunteers have been dismissed.
Panorama's seven-month investigation focused chiefly on uncovering a pattern of historical abuse - conducted by a number of different cadet leaders - in Glasgow, Birmingham and Hertfordshire.
'Take it like a man'
Martin was 12 when he was"systematically abused and raped repeatedly over many years" by his commanding officer Brian Leonard, at Tennal Grange cadet base in Birmingham.
He told Panorama: "You are trained to follow orders and you are trained to respect the officers and do as they tell you.
"That includes having to lie on the floor on a dirty blanket and just lie there and... take it like a man."
Panorama has spoken to 10 men who were abused by Leonard in the 1980s.
Martin says: "The thing was it was so blatantly obvious, it was almost as if it was hidden in full sight."
A girlfriend of one of the victims (who has chosen to remain anonymous) threatened to report Leonard to the police in 1987, but cadet officers pressured her to keep quiet.
The sergeant said he would take a statement from her, but warned her not to approach the police. No investigation into Leonard was ever carried out.
Leonard died in 1996, having never faced justice.
Tony was 14 when he joined Cheshunt Sea Cadets, in Hertfordshire, in 1979.
He said he woke to find his commanding officer Alan Waters at his bedside while he was on a weekend trip away.
Tony told Panorama: "I looked down and I was exposed… There was no doubt in my mind that he was touching me, no doubt in my mind whatsoever."
Terrified of returning, he told his parents - whose complaints were met with a home visit from two Sea Cadet officers, in full uniform.
Tony's parents were dissuaded from approaching the police by the officers and in return for not taking matters further, they were promised that Waters would be moved from looking after children.
But Panorama has discovered that he was not dismissed or even suspended - he was, in fact, promoted and moved to a division in North London where he was in charge of 10 Sea Cadet units.
What's more, concerns by other members of the corps after this appointment were dismissed by the very top - the Captain of the Sea Cadets - who said the allegations were "thoroughly investigated" and "not proved".
Waters was later convicted for separate child abuse offences in India in 2006 and placed on the Sex Offenders Register.
Panorama has found out that despite this, until March 2017 he held a title in a naval veterans' organisation - as honorary secretary of HMS President Retired Officers Association.
'Stuck in my mind'
Joe joined the Glasgow Highlanders Army Cadets in 1988 when he was 11. His Commanding Officer, John Fitzpatrick, would invite cadets to his flat, ply them with alcohol and sit them in front of pornographic films before bedtime.
Joe told Panorama: "I mean real hardcore stuff that I've never seen since I was in that guy's company…
"Images that have stuck in my mind to this day... if anybody had put images like that near my kids, I'd want to kill them."
On four occasions, Joe woke up to find Fitzpatrick sexually assaulting him.
Panorama has discovered that before Joe was abused, another cadet instructor - Gordon - had received complaints that Fitzpatrick had sexually assaulted another boy.
There were two young witnesses. Gordon went straight to the police, but instead of being congratulated his boss was furious.
Gordon told Panorama the boy's parents defied pressure from senior cadet figures and told the police.
The case went to trial - but Fitzpatrick was found "not proven". He was welcomed back into the cadets - taking up the position of CO again.
However, last year, Fitzpatrick was charged with lewd and libidinous behaviour against Joe and three other boys. This time the case was proven and he was sentenced to two years in prison.
The Birmingham case was one of the first cadet cases taken on by David McClenaghan, a child abuse solicitor from law firm BBK.
He told Panorama: "I have absolutely no doubt that the abuse in the cadets will mirror the other scandals like the Jimmy Savile case, like the abuse in the scouts, like abuse in the Catholic church."
But Napac's chief executive Gabrielle Shaw said the figures obtained by Panorama indicated that people were now more confident about coming forward to report abuse.
She added: "The onus is now on institutions such as the armed forces to deal fully and promptly with reported allegations."
The MoD told Panorama that today all adults who work with children undergo mandatory security and background checks, rigorous disclosure procedures and regular safeguard training.
A spokesman said: "We encourage anyone who has been a victim or knows someone who has to report it to the police."
The Marine Society and Sea Cadets (MSSC) apologised unreservedly for any hurt in regard to the case of Alan Waters and said what had happened was "not reflective of our organisation today".
The MSSC added: "We now have a zero tolerance protocol and a specialist team to enforce our policies and provide support."
For information and support for anyone affected by sexual abuse (current or historic) - including sources of support for children, young people and concerned parents - please see the listings on BBC Action Line.
Contact BBC Panorama - Do you have a story or information about any abuse/cover up related issue within the cadet forces which you want to share with BBC Panorama?