A recruitment drive launched to tackle the prison safety crisis has reached its target.
Ministers pledged to hire an additional 2,500 officers in 2016 as jails were hit by rising levels of violence, drug use and self-harm.
On Sunday, the Government announced it has passed the target seven months ahead of schedule.
Ministry of Justice figures show a net increase of 3,111 officers since October 2016, with most of the new recruits expected to be working on prison landings by the summer.
At the end of March there were 21,041 "full-time equivalent" personnel in frontline posts - the highest number for five years, but still below the level of around 25,000 seen at the beginning of the decade.
Staffing levels have repeatedly come under scrutiny as assaults and self-harm reached record levels across the prison estate in England and Wales.
There have also been a number of large-scale disturbances, while the availability and use of drugs behind bars has rocketed.
Justice Secretary David Gauke said there would be no let up in the recruitment drive despite the target having been met.
He said: "Going beyond this important milestone so early is a real achievement. It means the vast majority of these prison officers will be working on the landings by the summer, and all of them will be in place by the end of the year.
"This will make a real difference to the safety and security of our prisons, ensuring they can fulfil their purpose - protecting the public, reducing reoffending and crucially, rehabilitating offenders.
"But let me be clear - the recruitment drive continues and will continue until we reach required levels across the prison estate, with the same urgency that has secured this remarkable influx of new staff."