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Investing and savings platform Prosper is giving savers the chance to beat the base rate for three months with a 4.5 per cent micro-fix.

The account is provided by Santander International and comes with a regular interest rate of 3.75 per cent, which Prosper* will boost by 0.75 per cent.

If you locked away the minimum of £10,000 within the account, you'd earn around £110 after three months.

Last week the Bank of England voted to cut the base rate from 4.25 per cent to 4 per cent. Since then over 20 savings providers have slashed their variable savings rates, according to rates scrutineer Moneyfacts Compare.

It's still possible to find rates on savings accounts that are higher than the base rate – but you must keep a close eye on your options.

Prosper is an investing and savings platform that allows you to search for a savings account and then open the product that's right for you. Find out more about its 4.5 per cent fixed-term deposit account below.

> Open a 4.5 per cent three-month fixed savings account with Prosper*

How does this option fare?

The account from Santander International available through Prosper* is a three-month fixed-term deposit account. You choose the amount to lock away, which you can't access until the end of the fixed term.

The minimum you can deposit is £10,000 and the maximum is £1,000,000.

The standard interest rate is 3.75 per cent, which Santander International pays when the account matures.

Prosper tops this up by 0.75 per cent, paying the boost to your bank account the week after maturity.

This is Money says: With more providers set to decide whether to pass on the base rate cut to savers over the coming weeks, it's worth considering whether to give your savings a short-term boost with this option from Prosper.

You need to be prepared to keep your savings stashed away, because you can't access them until the end of the fixed term of mid-November. 

It's also not an Isa, meaning your savings aren't shielded from tax and so you should keep an eye on whether the interest you earn takes you over your personal savings allowance.

However, only interest earned from the underlying 3.75 per cent will be subject to tax. Prosper says that HMRC treats the 0.75 boost as a type of cashback and doesn't regard it as taxable income.

You can keep track of the best rates with our regularly updated savings tables.

In terms of cash Isas, Chip* currently has the best headline rate, offering 4.7 per cent. This includes a 1.66 per cent bonus for three months.

After this the rate plummets to 3.04 per cent, so you should think about transferring after – but it's worth considering as a tax-free, flexible alternative to Prosper's account.

> Find out more about Prosper's account*