Investment return will be based on 140 per cent of any growth in the FTSE 100 index, up to a maximum of 60 per cent above the initial investment. The original capital is protected in full, but must be invested for the full six-year term.

The investment can be placed in a stocks and shares ISA or used as a stand-alone investment. The minimum initial investment is £3,000 and the offer period runs from 15 October to 7 December 2007, but ISA/PEP transfers must be completed by 16 November 2007. The first investment term ends on 19 December 2013.

Ian Stuttard, director of savings and bancassurance at NatWest, said, ‘In today’s economic climate many investors are looking for a safe place to put their money for the medium to long term. The Capital Protected Investment offers a guarantee to protect the original investment while offering potentially excellent returns. This gives customers the opportunity to safely secure previous gains from other investments without sacrificing investment growth potential.

‘It is an ideal way to save towards retirement, children’s education or a special event, safe in the knowledge that your original money will be secure, but harnessing the potential of stock market growth.’