The trickle of consumer devices into the office has turned into a flood, sweeping away IT departments’ priorities and forcing them to rethink investments.

IT analyst firm TechMarketView calculates that five million employees in the UK are already using their own devices in the office as bring your own device (BYOD) momentum builds. This figure will rise to 9.5 million by 2016.

As a result, spending on related software services will grow from £176m ($280m) in 2012 to £675m ($1.1bn) by 2016. This rapid uptake of BYOD will force companies to rethink their IT spending, making them divert budget from other areas of IT spend to pay for BYOD projects.

IT departments will be spending more in areas such as security – especially encryption – mobile-device management, building enterprise application stores and infrastructure upgrades to support increased data loads due to hosting of virtualised data and applications for BYOD users.

And the BYOD revolution is bad news for companies supplying hardware and support because responsibility for support will shift to the employee and away from IT departments.

Phil Codling, research director and author of the report at TechMarketView said the BYOD trend is a “double-edged sword”, adding: “While rapid and sustained adoption will lead to a £2bn ($3.2bn) opportunity for the UK IT market, it will be a huge disruptor to supplier partnerships and business models.”

In particular the move to staff using their own devices in the workplace is bad news for desktop and mobile hardware suppliers who “need to find new business models and revenue drivers to counter this”, said Codling.

The report, BYOD: opportunities and threats from disruption, said two key groups of employees are driving BYOD: senior managers at board level asking IT to sync their personal devices with work and the number of younger employers entering the workplace with high expectations of using their personal devices with work applications – although the attitudes of this second group have been disputed.

“IT finds it harder to say no to senior management,” said Codling, which is one reason the BYOD trend is accelerating.