Could NHS £10 a month charge be a good thing

A few weeks ago, there was statement by Lord Warner suggesting  that a £10 month charge for NHS services could stop it sliding further into decline. See more at

http://www.theguardian.com/society/2014/mar/31/nhs-users-pay-membership-charge

It has proved controversial to a number of people as one of the core principals of the NHS is that it is for everyone, and free at point of use, so any charging mechanism is a difficult thing to swallow. However with a few changes i think a monthly charge could work.

• £10 a month is a lot of money for some but nothing for others, so I would change it to a sliding scale of charges with those unemployed paying nothing and those earning the most paying much much more. 
• a separate fee makes it very difficult to administer so I'd set it up to run via HMRC and take it directly from peoples payroll's and thus ensuring income is maximised. 
• In the same way we are moving to universal credit, we should also move to universal charging where all government charges are collected through the same general mechanism. We could call this system Income Tax?

So yes if the NHS needs more money to survive and to ensure we all get the services that we need then increasing costs need to be met by the country and a charge as suggested should be introduced, but instead of a separate charge why not just progressive and general taxation, its far simpler, fairer and requires less administration .