The most consistent cash ISAs

Worried you'll open a 'best buy' ISA only for the rate to drop soon after? If you open one of these consistently competitive cash ISAs, you won't need to keep transferring your cash...

If you haven't already noticed, ISA season is well underway, and many savers will be making that last minute dash to take advantage of their tax free allowance.

However, opening an ISA can sometimes be a bit of a gamble, and many ISAs which were storming the best buy tables this time last year now languish behind.

Of course, one way to combat this is to keep a close eye on your account to ensure you're getting a good deal. Provided your bank or building society doesn't impose any penalties, it's relatively easy to transfer your money from one ISA to another, or to open a new ISA with a different provider.

The problem is, many of the best deals don't allow transfers in, and you could end up with ISAs from several providers which are hard to keep track of. Besides, you may not even want to go through the hassle of transferring your cash every year, and decide to stick with the same account out of sheer apathy.

Substance over sexy rates

If you don't fancy juggling several accounts at once, the best way to ensure you're not lumbered with an uncompetitive ISA is to choose one that has offered consistently good returns.

Consistent ISAs aren't as obvious to spot as best buys, as they don't generate the same level of attention as the market-leading accounts.

However, the beauty of these ISAs is that they have provided the highest returns over the long term. So while they won't necessarily offer the highest rates at any one time, they are also unlikely to suddenly drop their rates six or twelve months down the line.

So, even if you don't have the time to chase the best buy deals or the patience to fill in endless forms, you can relax in the knowledge that your cash is earning a decent rate of return, even when your back's turned.

According to Moneyfacts, here are the most consistent internet ISAs over the past three years:

With a total return of almost £530 over three years, top pick is Kent Reliance's Direct Variable Cash ISA. Although the account may only pay 1.92% AER at the moment, healthy levels of interest have helped it yield the best overall returns over the past three years.

You can open one with as little as £1, and the account also accepts transfers in. Those under 25 also get a preferential rate of 2.02% - just for being young!

Second placed Tipton & Coseley Building Society currently pays a rate of 2% on its Premier ISA. However, the account has quite a few restrictions, and the tiny Midlands-based building society does not accept transfers in. In addition, it requires 30 days notice for any withdrawals, which may put you off.

A better alternative comes in the form of Yorkshire Building Society, which also pays the best interest rate of the three at the moment. Its e-ISA gives a return of 2.3% on balances from £10 and also allows transfers in.

It's interesting to note that over the shorter period of 18 months, yet another building society, Principality, takes the top spot for consistent returns. Its e-ISA currently pays 2.2% on balances from £1. It also accepts transfers from other providers.

Consider your options

Of course, past performance is no guarantee of future returns, and if it's rates that rule in your book, Barclays Golden ISA is the current market leader, paying 3.61% AER.

However, this account doesn't accept transfers in, and if last year's Barclays Tax Haven ISA is anything to go by, it probably won't be the market leader this time next year. Plus, Barclays had problems with its ISA customer service last year, causing inconvenience and delays for many customers.

Then again, I'm not suggesting you ignore the best deals, as market leading rates can boost your returns by tens, if not hundreds of pounds.

However, busy lives and bulging diaries can sometimes take priority over ISA transfers, and you may forget to check whether your savings are working as hard as they once did. In cases such as these, perhaps a consistent cash ISA is a very good idea, indeed...

More: Why NS&I isn't a good home for your savings / The top ten cash ISAs