The move to time limit ESA is effectively seeing the end of one of the key Universal Benefits.
Until October 2008 people who became unwell or disabled were able to claim Incapacity Benefit. In order to be eligible for Incapacity Benefit, you needed to be unemployed, or to have reached the end of your Statutory Sick Pay from an employer. You only needed to have paid enough National Insurance Contributions. There was no means testing, and no time limit. In fact Incapacity Benefit had three rates of pay, increasing over time.
In 2008, Employment and Support Allowance was brought in to replace IB. There are two possible ways of claiming ESA. You can either claim it on an income basis, through means testing. Or you can claim it on a contribution basis, the same as Incapacity Benefit. There is currently no time limit on claims for Contributory ESA. People are initially assessed through a phone interview, and then in person through a medical by ATOS. They are then assigned a group, either Support Group, or Work Related Activity Group.
As discussed elsewhere, this medical assessment has its faults. But at least if you managed to get onto ESA, there was no time limit for claiming it. If you remained ill and unable to work, your regular assessments would (in theory) allow you to stay on a higher rate of benefit, with a greater level of support from the DWP if you were working towards returning to employment.
The Spending Review changes means that people in receipt of Contribution based ESA, at the end of 12 months, will be reassessed for eligibility for Income Related ESA. They will be means tested. If they have a partner who works, then they will lose income. They may be transferred to JSA, which itself is time limited. Or they may not even be eligible for that, as it too is means tested.
This effectively sees the end of a Universal Sickness Benefit.
And puts those people, many of whom are seriously ill or disabled, in a situation of dependency on their partner, with greater expectations of engaging in work related activity, and far less support from the DWP.