This is not as simple to implement as Balls and the other Labour cronies think.
Council tax bands in England were established in 1991, and properties worth more than £320k at that date were set at the highest band, Band H. All other valuations since have been estimated by referencing back to that date.
There may be an approximate correlation between Band H and £2m valuation in today's money, but property price inflation is not uniform across the country. London is a case in point, where price inflation has been higher than average, bit again, with massive variations between districts.
The original valuations were done in 1991 using drive by chartered values who were paid to do it. There was then a period when objections were heard. Are we going to have the same palava again? It will be impossible to just say, everyone in Band H, you are liable for this.
It the the Valuation Agency that manages and controls this, not local authorities, who merely use the output data.
The devil is in the detail here, and it ain't simple.
Finally there is plenty of evidence in these parts of folks being advised to offer their country mansions for sale in the range up to £2.25m at a price of £1.95m. This has been going on since the summer.