The Tories had a similar scheme in the 1980s called the Youth Training Scheme (YTS).. As the named suggested, it was aimed at young unemployed, who were forced by the threat of loss of benefit to work peanuts. The scheme was mostly exploited by unscrupulous employers, who got a pool of young workers for next to nothing. It was not a great success and cost a fortune to run until it was scrapped.
The new proposals will, if they are daft enough to introduce such a thing, suffer the same fate.
The timing isn't good either, when Government cuts are likely to put another 2 million currently working and paying tax, into unemployment.