Greater Manchester Police has uncovered 6,155 crimes that weren't properly recorded in the last four months.
The offences, which have now been properly registered, were found as part of a 'due diligence' review launched after the force was plunged into crisis in December.
Today the force revealed 6,000 police officers have received refresher training designed to ensure cops put victims first as well as record and investigate crimes properly - with a further squad of 70 checkers - as part of a programme of modernisation to drag GMP out of 'special measures'.
A scathing report by the government's police inspectorate published in December - which cost Ian Hopkins his job as chief constable - estimated that the force had failed to properly record 80,000 crimes in one year, including one in four violent crimes.
It also slammed delayed, dropped and badly-planned investigations as well as expressing concerns about GMP's approach to domestic violence and child protection.
The force was effectively put in 'special measures', with Home Secretary Priti Patel describing the crisis at GMP as 'appalling' and announcing a 'recovery plan'.
Today (Thursday) Deputy Chief Constable Mabs Hussain outlined what action the force had taken to turn around the struggling police force.
He revealed that a review of 150,283 incidents between December and March had resulted in a further 6,155 crimes being recorded on GMP systems.
The force has also given refresher training to 6,000 police officers to help them put victims 'at the centre of everything we do' and make sure crimes are recorded properly, particularly where an incident might encompass multiple crimes but previously only one might be recorded.
A new 'Centralised Crime Recording Unit' has been launched with the aim of ensuring crimes are recorded properly and quickly so officers can dispatched with the correct information so they can 'hit the ground running', said the top cop.
Some 70 police officers across all ten GMP divisions have been tasked with checking crimes have been recorded properly.
The force has also piloted a 'Prisoner Processing Unit' in it's city centre division which is to be rolled out across all areas.
Officers in these units will 'own' an investigation from the moment of arrest through to court whilst keeping victims of crime regular updates, said DCC Hussain.
The force was recruiting more than 100 'investigators' into another new unit, the Crime Investigation Team, who will take witness statements and gather evidence, he said, adding that this would free up 'frontline' officers.
Officers on a fourth team introduced in early 2020, Criminal Justice Units, will ensure prosecution files 'are of the highest quality', he said.
The force is also conducting a review of police 'body-cam' footage from domestic abuse cases 'to see if we could have done more' for victims, said the senior officer.
DCC Hussain, in a message to the public, said: "Whilst it is clear we still have a lot of work to do to regain the confidence of the public, we are working hard to deliver the high-quality service you rightly expect of us.
"We are making progress, including rolling out new training for officers specifically aimed at supporting victims of crime, setting up three new units specifically dedicated to improve the service you receive, and a number of other key changes are underway which I can share today."
He concluded: "This is only the beginning and we will not stop learning, improving and striving to do better. We will not always get it right, but it is our and my commitment to you that we will be as open and honest on the measures and progress we are making.
"The improvements I have outlined today are thanks to the hard work of our dedicated officers and staff who come to work each day and work tirelessly to improve our service and find better ways of supporting victims."
GMP's in-coming chief constable Stephen Watson, currently at the helm of South Yorkshire Police, is due to start his new job at the end of May.
He has already hinted he may be forced to axe GMP's disastrous £27m IT system which was installed in July 2019, some 19 months behind schedule. It has been plagued with problems and has seen GMP absent from a succession of national crime statistics bulletins.
