Mervyn Davies, Standard Chartered’s chairman and an adviser to the Prime Minister, has voiced concern over the Government moving to a less competitive tax regime, claiming that it could be “hugely damaging”.

Mr Davies is the chairman of the Prime Minister’s advisory business council and his words come at a sensitive time for the Chancellor, Alistair Darling, a week before he delivers his first Budget.

Questioning both Mr Darling’s moves on capital gains tax as well as changes to the rules for non-domiciled taxpayers, Mr Davies said in an interview with the Financial Times: “The Government has to be extremely careful on tweaking and changing the taxation policy of this country. If we are not careful, it will make us uncompetitive.”

Gordon Brown set up the business council last year to conduct reviews on the areas that its members believed would “determine the future economic wellbeing of the UK”. It is also able to make recommendations for reform on areas it deems important.

Other members include Sir Stuart Rose, the chief executive of Marks & Spencer, Stephen Green, the HSBC chairman, Sir Richard Branson, the founder of Virgin Group, and Sir Rod Eddington, the former chief executive of British Airways.

Mr Davies said that the council had made its concerns clear to ministers in private. “Individuals have not been afraid to make that view very clear,” he said. “Do we comment individually on nondoms and CGT? Absolutely.”

European tax havens will be thrust into the limelight today as Germany looks for allies in its battle with Liechtenstein over the principality’s secretive banking laws.

Berlin will argue at the regular monthly meeting of European Union finance ministers that renewed pressure should be placed on havens such as Liechtenstein, Switzerland, Monaco, Andorra and San Marino to exchange information with national authorities inside the EU on foreign-held accounts. Germany will not table any formal proposals, but is expected to outline moves by arguing that there is a need to extend existing EU legislation on the taxation of interest from savings held in other member states to cover dividend payments and capital gains.

The initiative is likely to win support from Britain and other EU countries. One Brussels official said: “There is a lot of sympathy for the German position.”