Bearing in mind this is a Sunday newspaper story, it is still pretty alarming. It seems there are draft plans to introduce a national road toll scheme (possibly to replace the existing road tax, but it's not entirely clear), of upto 87p (USD1.57) per kilometre with around 10 different pricing bands based on the type of road being used - urban and trunk roads would apparently attract the highest levels of toll.
To accomplish this, though, it would be necessary to fit every vehicle with a chip so its location could be tracked by satellite so although it seems that the identity of the driver will not be tracked it will still represent a huge curtailment of individual privacy in practical terms, although according to the linked story 62% of those polled for a survey did not consider this a 'major issue; I am obviously part of the 'sizeable minority' which would have strong reservations.
Undoubtedly the meaning of the concept that 'overall' taxes would not rise needs to be examined further. It seems, from reading the article, that this is on a national level rather than an individual level. If so this imples that those who use urban or trunk roads regularly would end up paying considerably more than at present (a charge of 87p per kilometre would mount up VERY rapidly) and if overall taxes are not to rise then some rural drivers would end up paying practically nothing. I think the implications of this will not take long to be appreciated by the urban majority and the government which passes the law to allow this to happen will pay the price at the election following its introduction. For this reason alone I suspect this whole notion is simply being floated to test public reaction and like many other hare-brained schemes of this government will either disappear without trace or have to be modified dramatically.
Also it seems to me that the cost of maintaining a kilometre of rural road per user must be considerably higher than the unit cost of maintaining highly-used roads, although the charging system proposed will be weighted toward the most heavily-used routes. Rural drivers will be subsidised even more highly than they probably are at present.
In summary, apart from being (in my view) an intolerable extension of surveillance by the state on huge numbers of citizens, this scheme is more about raising taxes by stealth than it is anything to do with cutting down hydrocarbon emissions. The claim that overall taxes would not rise is hard to beleive.