Tax and the Minimum Wage

The Lib Dems list a number of achievements in the coalition government. Whatever we might think, one does stand out as a real achievement and that is the increase in the basic tax allowance, which will be £10,000 from April 2014. A manifesto pledge fulfilled then. However, like so many reforms this could easily be left for inflation to erode if we are no longer in government. So, I'd like to see a new policy; a new target. To link the basic tax allowance to the minimum wage and take it out of the political arena altogether. 
Let's challenge the Tories and Labour. A tax allowance that is set at the minimum wage for a 35 hour week and the link permanently maintained. That would be £11485 pounds. A good policy and fair. Simply logical too. Surely a minimum wage is the minimum we should expect anyone to live on? So it shouldn't be taxed.