One thousand police jobs will go as the force attempts to cut £56million from its budget by 2020.
The cuts follow £50million of savings which have been made over the past five years as part of the Serving Sussex 2015 programme.
The job losses were announced today (Tuesday March 10) as Chief Constable Giles York unveiled the force’s “vision for policing Sussex in 2020”.
Mr York said: “Now we must trim further and to do so we have to look at our most significant area of cost - our people.
“We will be a smaller organisation with 700 fewer officers and staff - 500 police officers and 200 staff - delivering local policing over the next five years.
“A further 300 posts elsewhere in the force will go as we seek to save a further £56 million by 2020.
Now we must trim further and to do so we have to look at our most significant area of cost - our peopleChief Constable Giles York
“As an organisation we spend 80% of our budget on pay and with budget reductions we must refocus roles if we are to retain our ability to keep people safe.”
Mr York insisted Sussex in 2020 would be a service that “protects the community, is relentless in the pursuit of criminals and has an empowered workforce with integrity at its core”.
He added: “It is only by changing the way we deliver our service that we will be able to maintain the level of public safety we have achieved in Sussex. It’s absolutely paramount that we respond when people face significant risk and harm.
“I am starkly aware that there will be a lot of public interest in how this will affect them and I am also aware that some will experience a reduction in some parts of policing that are very dear to them.
“We will continue to prioritise crimes that cause the greatest harm to victims and the community such as harmful anti-social behaviour incidents.”
A spokesman for Sussex Police said Sussex in 2020 was designed to meet the priorities in Sussex Police and Crime Commissioner Katy Bourne’s Police and Crime Plan.
It took nearly six months to create and sets out local policing in terms of prevention, response and investigation across the county.
Mr York added: “The world we live in is changing and will continue to do so, including the crimes people commit.
“Our new model, which will be implemented in stages over the next four years, shapes our service so we are best equipped to meet emerging threats, within our financial constraints.”