You can put up to £20,000 into one or several ISAs (remember, you can’t have more than one of the same type of ISA in a single tax year) but you can’t roll over any unused allowance – so use it or lose it.

If you’re going down the stocks and shares ISA route, deciding where to invest your money is never easy. And this year, there’s an added nuisance: Brexit.

One in four investors are still waiting for clarity from MPs on a Brexit deal before they make any investment decisions, according to Interactive Investor.

While waiting for a clearer Brexit picture to emerge is understandable, delaying your decision too long could mean losing your valuable ISA allowance.

Luckily, there is a solution.

Investment platforms allow you to temporarily ‘park’ your money in cash within an ISA. You can then invest it as and when you’re ready.

So, you don’t have to decide straightaway where to invest but you don’t waste any of your allowance either.

However, this shouldn’t be a long-term solution because your money will be earning very little, or in some cases, no interest.

How much does it cost?

We contacted seven major ISA providers to find out how much they charge to leave your money in cash in a stocks and shares ISA and if they pay interest.

AJ Bell – no charge for money held in cash. No interest on £10,000 or less, 0.1% on £10,000-£50,000, 0.15% on £50,000+.

Bestinvest – no charge for money held in cash. Interest of 0.4% below Bank of England base rate.

Fidelity – no charge for money held in cash. No interest.

Hargreaves Lansdown – no charge for money held in cash. Interest of 0.1% on £4,999.99 or less and 0.15% on £5,000+.

Interactive Investor – charge a flat fee of £22.50 per quarter (returned as trading credits) regardless of underlying holdings. No interest.

The Share Centre – £4.80 a month to leave some of allowance in cash. No interest.

Nutmeg – 0.25% management fee. Interest of 0.40%.