The government is searching for IT providers able to supply emergency services and communications framework and equipment, set to be worth between £550m and £1.2bn.
The procurement process is being led by The Crime and Policing Group on behalf of the Department for Communities and Local Government, the Department of Health and both the Scottish and Welsh governments.
The current Emergency Services Mobile Communications Programme (ESMCP) expires in 2016.
It delivers voice and data services to each of the three emergency UK services via the Emergency Services Network (ESN).
A contract notice revealed the need for a replacement framework states that prospective suppliers will be expected to provide mobile communications and networking kit, fulfilling the security and coverage requirements of the three services.
Helpdesk, radio and data-management services are also required, besides software support and maintenance.
The contract is divided into four lots, covering ESN Delivery Partner, ESN User Services, ESN Mobile Services and ESN Extension services.
The tender explains the deal will last for five and a half years with the option to extend by 18 months.
An expected number of three providers are expected to be chosen for each lot, with a maximum number of six, but there are restrictions on the number of lots that can be bid for.
Those interested in lot one can only choose lot one, whereas those bidding on lot four may be entitled to win either two or three as well.
The notice also adds that the successful bidder will be responsible for providing technology that will be accessed by 250,000 staff within emergency services, 44 Police and crime commissioners, 13 ambulance trusts, the National Crime Agency, the Police Air Service, the British Transport Police, the Ministry of Defence Police and the Civil Nuclear Constabulary.