By Chris Dorrell The government should introduce a banded inheritance tax system to make the levy more progressive, a leading think tank said today. Demos urged the government to make inheritance tax fairer by introducing different bands. This would replace the current 40 per cent flat rate, which applies on any estate worth more than £325,000. The think tank suggested that there should be a 30 per cent rate on estates worth less than £1m and a 45 per cent tax rate for estates worth more than £2m. The 40 per cent rate should be retained for estates worth between £1-2m. Demos said these changes…