Savers looking for a home for their cash can now earn one of the highest fixed ISA rates on the market.
The latest deal could generate more than £900 in tax-free interest over a year for those using their full ISA allowance.
Vanquis Bank has moved to the top of the fixed-rate Cash ISA tables after increasing the rate on its one-year account to 4.66 per cent AER.
The account has been awarded a Best Buy label and an Excellent product rating by Moneyfactscompare.co.uk following the rate rise.
Caitlyn Eastell, Personal Finance Analyst at Moneyfactscompare.co.uk, said: "Vanquis Bank has increased the rate on its range of Fixed Rate Cash ISAs this week.
"The account which fares best is the one-year option, which has seen a boost to 4.66 per cent AER and takes the market-leading position."
She added: "On assessment, this account takes the top position as a 'Best Buy' and receives an Excellent Moneyfacts product rating."
The account requires a minimum deposit of £1,000 and allows savers to hold up to £250,000.
Anyone investing the full £20,000 ISA allowance would earn more than £900 in tax-free interest over the 12-month term.
Interest can be paid either on the account's anniversary or monthly, with the latter option carrying a slightly lower gross rate of 4.56 per cent.
Savers looking to secure a guaranteed return on their cash may want to act quickly | GETTYHowever, savers should be aware that accessing funds before the term ends comes with a penalty equivalent to 90 days' worth of interest.
Additional deposits are permitted within the first 30 days of opening, but must be made through a nominated account.
The ISA accepts transfers from both Cash and Stocks and Shares ISAs.
Despite competitive deals now available, a vast sum of money remains trapped in poorly performing accounts across the country.
Despite competitive deals now available, a vast sum of money remains trapped in poorly performing accounts across the country
| GETTYAnalysis of CACI data reveals that £146billion currently sits in 62 million adult savings accounts with balances up to £20,000, all earning less than three per cent interest.
The weighted average rate on these balances amounts to just 1.45 per cent.
This means British savers are collectively forgoing more than £4billion in additional interest they could be earning by switching to better-paying alternatives.
Nearly 11 million of these accounts hold between £5,000 and £20,000, with an average balance of £10,251 and an average weighted interest rate of only 1.48 per cent.
For savers holding the average balance of £10,251 in these underperforming accounts, the difference in returns is stark
| GETTYFor savers holding the average balance of £10,251 in these underperforming accounts, the difference in returns is stark.
At the typical rate of 1.48 per cent, such a balance would generate just £155 in annual interest.
Moving that same sum to a competitive easy access account paying 4.30 per cent would yield £444 instead, representing nearly three times the return.
Spring, the savings app which recently launched a Special Edition Easy Saver at 4.30 per cent AER to mark its first anniversary, highlighted the scale of missed opportunity.
Derek Sprawling, Head of Money at Spring, said: "There is £146billion sat in adult savings accounts with balances of up to £20,000 receiving a weighted average rate of under 1.50 per cent."