The DWP Information Sharing Designation Order [*extract of summary below] gives DWP and it’s Providers powers to share and exchange your personal data/information with employers and workfare hosts.
To mitigate against DWP and Work Programme providers sharing and obtaining your personal data, see section 1.1 of http://refuted.org.uk/2013/10/12/withhold/ which could be adapted for other DWP back to work schemes. As well as considering whether any DWP provider forms need signing, as they can and often do include a consent based voluntary agreement to share your personal data.
Notes: Welfare rights law and DWP guidance, in particular, changes frequently.
You may find more recent information via http://refuted.org.uk/category/ or by using the website search facility (top right)