Martin Hearson: We identified over 8,000 firms hiding in tax havens

The Government is considering relaxing anti-tax avoidance legislation known as Controlled Foreign Company rules

David Gauke, the minister responsible for taxation, has urged businesses to open themselves to greater scrutiny, saying that transparency could "lead to a more informed public debate on tax".

ActionAid's research today does exactly that. We have identified 8,492 tax haven-registered companies owned by FTSE 100 businesses, a number far bigger than previously disclosed. In most cases the information had to be dragged out of them through a series of complaints submitted to Companies House.

One reason businesses use tax havens is to avoid their tax obligations, in the UK and overseas. The tax benefits are also often combined with financial secrecy, which obscures tax planning structures from the public and even from revenue authorities in other countries.

The Government is considering relaxing anti-tax avoidance legislation known as Controlled Foreign Company rules. This would give an £840m tax break to British multinationals who use tax havens but would also make it easier for them to use tax havens to dodge taxes in developing countries.

The Government deserves credit for its commitment to overseas aid. Yet making it easier for the UK's biggest companies to dodge taxes in developing countries will just take money away from the governments we are supporting through aid.

Martin Hearson is a tax policy expert at ActionAid.