Santander has launched several best buy fixed-rate cash Isas joining other major banks battling for tax-free cash at the start of the new financial year.

It is offering 4.5 per cent on one, two, three and five year cash Isas – and you don't have to be an existing customer to get it.

The accounts accept transfers in, and can be opened with a minimum of £500 in branch, by mobile or online.

For those transferring in Isa balances of a minimum £10,000 from elsewhere, Santander is also offering vouchers.

For transfers between £10,000 and £24,999, savers get a £50 e-voucher to use at brands including Amazon, Costa and Tesco.

On a £10,000 transfer, adding the voucher roughly means a return of 4.98 per cent – figures calculated using our lump sum savings tool.

On transfers of £25,000 to £49,999 it's a £100 voucher; £200 for £50,000 to £99,999; and £400 for transfers in beyond £100,000.

The accounts are protected up to £120,000 under the Financial Services Compensation Scheme.

Andrew Hagger, personal finance expert at Moneycomms, said: 'Fierce competition in the Isa golden window shows no sign of subsiding.

'The 4.5 per cent deals from Santander are excellent value and even more so with the additional bonus e-vouchers - I expect this to be a successful promotion for Santander.'

For longer fixes, it's imperative to that you don't access to the funds before maturity – or you'll face a 120 days' interest charge.

HSBC last week also launched a best buy 4.5 per cent one-year fix. However, that is only open to existing current account holders.

Nationwide launched best buy fixed-rates before the end of the last tax year, including 4.5 per cent fixed for three and five years. 

It offers 4.35 per cent over one-year. That is open to new and existing customers.

NatWest and Barclays scrape into the This is Money independent best buy cash Isa tables with rates of 4.05 and 4 per cent respectively over one year.

However, the bigger banks are largely neglecting easy-access tax-free accounts. Top of the charts is Trading 212* with a 4.61 per cent rate.

The best you can get with a high street name is Virgin Money, with a 4.15 per cent rate. This is only available online.

A number of smaller building societies are also on the list, including Cambridge Building Society offering 4.1 per cent and Harpenden Building Society at 4.06 per cent.

But many of these smaller mutuals only accept customers from the certain postcodes.

The cash Isa limit for 2026/27 is £20,000. However, from the next financial year - 2027/28 - under 65s will have a smaller £12,000 annual limit.

The stocks and shares Isa investing limit will remain at £20,000. It means from April 2027, the maximum an under 65 can save into a cash Isa is £12,000 for that financial year - and the rest can still go into an investing Isa.