as the last poster quoted, still in consultation stage.
one other thing to be concerned with is the merging of national insurance contributions to become "earnings tax" thus if your employer does not pay in contributions or you as self employed dont pay the contributions, that can then also be used by HMRC to raid your bank account once the totals owd get large enough.
the reason i say this is that NI contributions have more error variance on if a employer pays the right amount, then compared to the error variance of income tax they pay HMRC through the PAYE system
basically employers get NI wrong more so then income tax, and most employee's/self employed dont realise it. but then with this new HMRC proposal, it will make the employee accountable to fill the deficit and not the employer.
other news which makes things worse is that government want to give employers tax breaks
*1., meaning yep you guessed it. while employers dont pay as much "earnings tax" on behalf of their employee, employee's are left to 'fit the bill'
*1. http://www.accountingweb.co.uk/article/employment-allowance-2000-nic-break-unveiled/539156