Nearly half of priority calls to 10111, the police emergency number, are not attended to, or officers arrive late on crime scenes.
This is thanks to vandals who have destroyed critical police radio infrastructure in Gauteng, leaving officers unable to respond to thousands of calls for help, the South African Policing Union (Sapu) says.
Over 40% of the province's radio masts, which link the 10111 emergency call centre in Midrand and police stations to officers on the road, have been destroyed, the union says.
The effect, says the union, is that nearly 50% of priority calls - calls about crimes in progress - fall through the cracks.
Since October vandals have been stripping masts, often located in remote areas, of copper cables and generators.
Sapu says that of the 66 masts in Gauteng, 25 have been destroyed - the majority covering critical policing areas including the Johannesburg and Pretoria CBDs.
Gauteng police spokesperson Col Lungelo Dlamini and national spokesperson Brig Vish Naidoo said they could not disclose operational information, but admitted glitches.
"Spares are available to service towers that may experience technical problems. Towers are being monitored.
"We have mechanisms in place … so that service delivery is not compromised," Dlamini said.
"Technical problems are being experienced and attended [to] from time to time. Should areas experience radio communication problems, there is a possibility that affected stations may change channels and use nearby towers for communication purposes."
Naidoo disputed Sapu's claims of 25 masts vandalised saying it's more likely to be five.
Richard Mamabolo, Police and Prisons Civil Rights Union spokesperson, said signal losses were compromising policing in Gauteng.
"The union is raising this issue with police management to demand to know what is being done to fix the problem," he said.
10111 operators who spoke on agreement of anonymity said vast areas of the province were being left in "radio darkness".
One dispatcher said: "While the specialised units have their own operating channels, when in areas where masts are down, their radios are useless.
"The mast in Laudium [in Tshwane], a critical communication point, went down in October. It's still down."
When the Sunday Times visited the site, all that remained of the infrastructure was the mast's structure and its burnt-out generator housing. The generator and copper cabling were missing.
A Pretoria police officer knows what that vandalism leads to. He was on duty when Atteridgeville constable Thembi Phadziri was killed by a drunk driver on December 15 at a roadblock on the R511 near Hartbeespoort Dam.
"We tried to use radio to establish where on the R511 they were, but the radios were dead. Officers at the station could only say the scene was on the R511. We eventually found our colleagues near the N4 interchange," the officer said.
A flying squad officer said it was a daily guess whether their radios would work.
"We know crimes are being committed but don't know where. We hope our colleagues who are in an area where there is radio signal have the time to phone or WhatsApp if something happens."
Sapu president Mpho Kwinika said police management must explain why the masts were not being repaired.
"We are not blaming management for the vandalism, but they must fix the masts. Reaction times to crimes has become slower, with delays of up to 30 minutes on a good day. On a bad day some crimes are not responded to," Kwinika said.
Kwinika said the union had raised the issue with provincial police management last month, with the matter discussed in a police management meeting this past week, but no response had been received.
Gauteng Community Policing Forum (CPF) chairperson Thokozani Masilela said the impact was in the delays in police responding to hijackings and armed robberies.
"In an attempted robbery at Reef Shopping Centre in Germiston in October police arrived 30 minutes after CPF officials arrived. They only responded after a CPF member phoned an officer on his cellphone," he said...