Rugged Android Equipment
Hopefully they will choose the Android route instead of Apple or Windows Phone. The reason being that there is already Android based rugged equipment designed for law enforcement, construction, military etc, which is designed to survive drops, rain and general abuse. There is also appropriate accessories for those, such as vehicle mounts and other related hardware that already exist, rather than having to be procured later. It is also likely that these would have replaceable batteries, which would prevent the devices having to be left on desks/in the police car to charge, rather than being where it's needed.
The arguments about the competitors are that Apple products are generally fragile, expensive and have no replaceable/repairable parts. Yes, you could put an armoured case on an iPad, but underneath, it's still a fragile device that will likely get damaged at some point. They're also not waterproof, so would likely need a case that would fully enclose it. This would potentially make the touch screen difficult to operate. Also, when the device inevitably gets damaged, it would be an expensive replacement/repair that would have to be returned to Apple, rather than the Police's IT department. Finally, if any accessories were required, they would have to be procured by a likely expensive process to custom build what was required. All of this ancillary equipment would likely then have to be scrapped due to Apple changing the shape/size of the device or the shape/location of the connectors. (And knowing the amount of time it takes to procure this equipment, the design would change half way through the process, causing loads of money to be wasted redesigning and reissuing replacement kit).
The same argument goes for Windows Phone, in that it's still a fragile device in a rugged case, although there are a couple of rugged phones available with this OS. There's also the potential that it will be discontinued if its market share stays low or decreases due to lack of demand or competitors, leaving the police to risk using unsupported equipment or having to pay for another procurement process.
Overall, the Android equipment is probably the most suitable for this sort of work. There is a possibility that this will have the highest cost due to the heavy duty requirements of the devices. However, it will probably outweigh the other devices, as there is a potential that Apple and Windows devices would be expensive to procure and adapt for their intended use, and they may spend more time being returned for repair or replacement due to them not being designed for rugged use. The Android equipment would likely also be supported by the manufacturer, being able to supply new devices, accessories and spare parts for the duration of their use. This would be the be the best option to spend taxpayer's money on.