Offshore tax havens still have their uses for tax planning, advisers say – in spite of a new raft of rules to limit bank secrecy and discourage Britons from moving money outside the UK.

Switzerland, Austria, Luxembourg and Macau are among the latest jurisdictions to agree to implement standards for transparency set by the Organisation for Economic Co-operation and Development (OECD).

Regulators from the US Internal Revenue Service, meanwhile, are pressing UBS for the records of wealthy Americans. And world leaders at this week’s G20 summit agreed to take action against “uncooperative” offshore centres.

Indeed, the recent string of concessions on tax secrecy by the world’s leading private wealth centres is considered a breakthrough in the global assault on tax evasion being waged by the US, the UK and most European governments.

UK prime minister Gordon Brown and US president Barack Obama have both said eradicating tax havens is a priority – at a time when tax revenues are shrinking as a result of the economic crisis.

So, where does this leave private investors with portfolios offshore? The consensus is that while tax havens still offer benefits – particularly for non-domiciled UK residents looking to keep assets outside the Revenue’s tax net – their usefulness is diminishing.

So, while global markets are under siege, many investors are being advised to keep their portfolios within the UK.

“One of the fundamental problems is that offshore tax havens have had a lot of bad press,” says Steve Georgala, managing director of Maitland, the advisory firm. “It’s not easy for someone to move large chunks of money from one place to another. It’s not as if you wake up one morning and say ‘I’m going to bank offshore and not tell anyone about it’.”

The traditional way to take advantage of a tax haven is either to move there and become a resident for tax purposes, or to transfer assets to a company or a trust held within the jurisdiction to reduce tax paid on capital gains and income.

The Channel Islands – Jersey and Guernsey – and the Isle of Man are popular in both regards for UK residents, as are the Cayman Islands and Monaco where no income tax is paid.

However, offshore regulatory regimes are changing.

Guernsey has been forced to adapt its tax policy in the face of international criticism of harmful tax practices. The island has complied fully with the EU Code of Conduct on Business Taxation and the International Monetary Fund is to reassess its financial, regulatory and criminal justice structure.

Jersey has revamped its tax structures and increased co-operation with other jurisdictions in the exchange of information. Critics had attacked the fact that Jersey levied no tax on the corporate profits of companies with non-resident shareholders, while charging companies owned by resident shareholders 20 per cent.

But gaining residency in Jersey has long been perceived as a difficult process. The much-coveted 1(1)K status is reserved for wealthy individuals.

These residents pay a minimum of £100,000 a year in income tax. The first £1m of their taxable global income is taxed at 20 per cent, the next £500,000 at 10 per cent and anything above that at 1 per cent. So it is not worth considering a move if your taxable income is less than £500,000.

For investors planning to remain in the UK but wanting to keep some money in tax-advantaged jurisdictions, offshore investment bonds offer two advantages.

First, all income and capital gains within the bond are tax-free when they arise if they are never brought into the UK, apart from certain withholding taxes that may apply to dividends arising from UK equities or funds.

Second, up to 5 per cent of the original capital invested may be withdrawn each year, for 20 years, with the tax on the withdrawal deferred until the bond is encashed.