DAVID Cameron's confession that he had benefited from a stake in an offshore fund has reignited public anger about the tax affairs of the wealthy.

It threw the spotlight back onto Cameron's public criticism in 2012 that it was "morally wrong" for comedian Jimmy Carr and others to use tax schemes - since attacked by HMRC - that enabled them to pay tax on only one per cent of their income.

For ordinary Scots who do have to pay all their taxes, the new tax year arrived on Wednesday, and with it a raft of changes to tax, on savings, and investments.

More than half of 2,000 people surveyed by Skipton Building Society said they were confused by the rules associated with Individual Savings Accounts (Isas) and over one-third had never heard of the Personal Savings Allowance.

The PSA, new for this tax year, means you can earn up to £1,000 a year in savings interest tax-free, or £500 if you are a higher-rate taxpayer, all on top of the £15,240 you can pay into an Isa.

Savings providers will no longer deduct tax from the interest they pay out. If your interest exceeds the limit, it will have to be declared on a self-assessment tax form but for those on PAYE it may then be incorporated into your next tax code.

The allowance covers interest from all savings products and from corporate or Government bonds. Most people won't need an Isa to avoid paying tax on their savings - if you are earning a rate of 1.5 per cent you can hold up to £75,000 tax-free, or £37,500 on a rate of three per cent.

But savings pots can build up, and interest rates may eventually rise, so Isas are not dead.

For those who are still confused, there are now six Isas in the family, with one more on the way.

The £15,240 limit covers total contributions into cash and shares Isas and into the new Innovative Finance Isa, which covers peer-to-peer lending platforms such as Zopa and RateSetter. Those and other big brands, however, are still awaiting authorisation to issue the new Isa, with only 11 smaller platforms so far through the approval process.

The Junior Isa carries a separate £4,080 annual allowance for under-18s and cannot be accessed until the child is 18.

Meanwhile, the Help to Buy Isa allows you to save up to £12,000 over five years and receive £1 from the Government for every £4 saved towards a first home deposit.

The overall Isa allowance will rise to £20,000 in April 2017 and also cover a new Lifetime Isa.

There is also a new allowance for people earning dividends from funds or shares. You will now be able to earn £5,000 in dividends without paying any tax. For anyone who has declared dividend income on a tax form in the past, HMRC will assume you will receive the same level of income in the current tax year. If this will not be the case, you need to contact HMRC to avoid an unfavourable tax code. The income tax personal allowance has been raised from £10,600 so that we now won't have to pay any tax on the first £11,000 we earn. The threshold at which people move from basic rate to higher rate tax has also risen, from £42,385 to £43,000.

Also new is the increased power over tax rates for the Scottish Government, which could see the higher rate threshold held down in 2017-18 rather than rising towards £50,000 as promised by Chancellor George Osborne.