West Yorkshire Police Federation has condemned the Prime Minister's legacy in the police force following her announcement on Friday that she would step down.
In a speech outside 10 Downing Street on Friday, Mrs May announced her resignation.
She will quit as Conservative leader on 7 June, paving the way for a contest to decide a new prime minister.
In a statement on social media, the West Yorkshire Police Federation, the staff association for police constables, sergeants and inspectors, said: “Under nine years of Theresa May, policing has suffered cruel cuts that have brought the service to its knees. Things can only get better.”
It continues: "Theresa May's Legacy - when she became Home Secretary in 2010 there were 143,734 police officers in England and Wales.
"As she exits as PM there are now 122,395, 21,339 fewer.
"There are also 15,894 fewer members of police staff.
"Cuts have consequences."
West Yorkshire Police Federation Chairman Brian Booth said: "My colleagues will be breathing a sigh of relief with the news announced today that Theresa May will be standing down as Prime Minister.
“Under her reign in Parliament, policing has suffered cruel cuts that have brought the service to its knees. Things can only get better.
“I hope the next Prime Minister listens to all the key stake holders and returns policing back to what it was before.
“A service that is – well it certainly was - known to be the best in the world.”