A bit of understatement
"However, IDS confessed last week that the target could no longer be reached as at least 700,000 people seeking Employment Support Allowance will still be absent from the new system a little over three years from now."
So they'll just need to keep one old system running for a while longer then ..... unless ... perhaps .... he wasn't being .... quite as open as he might have been ....
because people claiming ESA might have children, so the child tax credit system will have to be kept running by HMRC, who will also have to carry on running working tax credit for those who were working before becoming sick or with working partners. Some of these ESA claimants might be paying rent so that will mean that housing benefit will have to continue - in every local authority in the UK - as well.
Then there are the major changes to means-tested benefits for older people, which hinge around the introduction of single-tier pensions in 2016, and which have to be coordinated with Universal Credit timetables because of rule changes on age and many other reasons. I wonder (whistles innocently) what might be happening around IT development for the two new pension credit schemes due to start then?