The Government needs to do more to tackle tax-dodging on British turf ahead of G8 talks on an anti-evasion deal, David Cameron has admitted.

The Prime Minister said "a lot of progress" had been made toughening up systems in crown dependencies and overseas territories, but he insisted that the process "could go further".

The comments came after the IF coalition of leading charities warned that the UK had to get its "own house in order" before the G8 summit in Northern Ireland next month.

In a letter to the premier, they welcomed his commitment to cracking down on tax avoidance.

"We'd urge you to ensure that the G8 publishes a clear, timed plan of how poor developing countries will benefit from any G8 tax agreement," the letter said. "Getting the UK's own house in order ahead of the G8 Leaders' Summit is an essential step towards this.

"This would require that the UK's Crown Dependencies and Overseas Territories sign the existing Multilateral Convention on Mutual Administrative Assistance in Tax Matters immediately and in advance of the G8.

"At the G8 they should implement a new gold standard on beneficial ownership and agree to share information in a multilateral and automatic basis.

"This will ensure that they can no longer harbour tax evaders and money launderers that deprive poor countries of valuable resources that could be invested in tackling hunger, and truly would pave the way for a historic G8 tax agreement."

Mr Cameron, who will be attending the United Nations high level panel on development during his visit to the US this week, said: "I accept that we need to take further action with regards to the crown dependencies and overseas territories. A lot of progress has been made in recent weeks and a number of arrangements have been made, but I think we can go further and we are having a number of conversations about that.

"But the overall aim here is to find the best possible mechanism to make sure that companies share their tax information with the tax authorities and the tax authorities accurately share their information with each other. I am confident we are going to make some real progress on this at the G8 and G20. We won't do everything I would like to do or everything some of the lobby groups would like to do, but I am confident we are going to make some real progress."