This excerpt taken from the ICI 6-K filed Mar 16, 2005.
Taxation of dividends paid to US Shareholders
An individual shareholder who is resident in the UK for UK tax purposes and who receives a dividend from the Company is entitled to claim a tax credit in the UK against his/her income tax liability attributable to the dividend.
US resident shareholders should note that under the New Convention no foreign tax credit is available in respect of any associated tax credit or UK withholding with respect to any dividend payment.
No dividends received deduction is allowed to US resident corporate shareholders with respect to dividends paid by the Company.
Subject to applicable limitations that may vary depending upon a US resident shareholders individual circumstances, dividends paid to non-corporate US resident shareholders in taxable years beginning before 1 January 2009 will be taxable at a maximum tax rate of 15%. Non-corporate US resident shareholders should consult their own tax advisers to determine whether they are subject to any special rules that limit their ability to be taxed at this favourable rate.