Police response times to the most serious crimes in Sussex were slower in 2013 compared with two years before, according to official figures.

Officers reached 9.1% fewer crimes within the target time, according to figures obtained by the Labour Party.

The force’s self-imposed target is to respond to Grade 1 calls - requiring immediate police attendance - within 15 minutes 80% of the time and to Grade 2 calls - requiring the earliest possible police attendance - within an hour 80% of the time.

In September 2013 Sussex Police fell short on both counts, arriving within target times for 78.6% of Grade 1 calls and 65% of Grade 2 calls.

The Labour party blamed nationwide cuts in the number of police response officers.

Sussex Police declined to explain why response times were drastically slower in 2013 when compared with 2011, instead offering figures for April 2014 which show officers arrived within the target time for 84% of Grade 1 “emergency” calls and 81% of Grade 2 “priority” calls.

The spokesman said: “During last year an HMIC inspection showed that Sussex Police over the two preceding years to September 2013 had not met the target.

“In response to the inspection a working group chaired by Supt Hobbs was set up to improve performance across the force. That work is ongoing.”

In July last year The Argus reported how Detective Sergeant Paul Sellings, of the Police Federation, claimed Grade 1 emergency calls were going unanswered in Brighton because there were not enough officers to respond to them.

But in October Chief Constable Martin Richards claimed failure to reach response time targets were due to a “technical anomaly” in how officers recorded their arrival at the scene of a crime – a change from an automatic system to a manual one requiring officers to press a button or radio in their arrival.

He said officers would sometimes forget to log their arrival, affecting the force’s response times.

Sussex Police & Crime Commissioner Katy Bourne said: “I am aware this has been a concern for residents, which is why I have previously raised this issue with the Chief Constable during our regular performance and accountability meetings.

“As a result the Force has reviewed its emergency response model and improvements have been made. I believe Sussex residents deserve the very best police force and this is something I will continue to hold the Chief Constable to account for.”