At FairHomeTax we commissioned three major CEBR Economic reviews. The second clearly shows that a review of Council Tax is long overdue and by adding new bands onto the more expensive properties, this would indeed generate a more effective, fairer and progressive tax raising process that would be better than Mansion Tax. http://www.fairhometax.uk/FairCouncilTax_CEBR.html
The esteemed journalist Simon Jenkins for the left of centre newspaper the Guardian seems to agree. here's an extract from his article today: "A gap then emerged between advocates of Cable’s mansion tax, which would go to the Treasury, and those who wanted to reform council tax, which goes to local councils. The clearest need was to reform the top band, which had been fixed in 1991 at £320,000 (roughly £1m with house-price inflation today). When a higher band was introduced in Wales in 2005, starting at £424,000, it caused little fuss."