Final details have been confirmed for the second amnesty in which the taxman will try to persuade people with offshore bank accounts to declare income earned as interest.

Dave Hartnett, permanent secretary for tax at HMRC, confirmed a national campaign, including newspaper advertising, will run to promote the new amnesty - or new disclosure order(NDO). The NDO has been allocated a budget and though he would not confirm the sum involved, he said: 'It isn't colossal.'

The amnesty will begin on 1 September, with taxpayers able to submit paper disclosures. Those making online disclosures will have to wait until 1 October to submit their notice of unpaid tax.

Those making online disclosures will have until 12 March, and taxpayers would have until 31 January to come forward if volunteering information on paper, clashing with the annual self-assessment deadline.

Tax experts who spoke to Accountancy Age expressed concern over the timings. One said it will 'put real pressure on small accountants already dealing with the nightmare of the influx of self-assessment'.

Hartnett said he is pushing for taxpayers to make disclosures online. 'It takes a while to build up but we'd like to think there will be more disclosures online this time,' he said.