In the first Labour Budget in 14 years, Chancellor Rachel Reeves unveiled £40billion worth of Budget tax increases to fill a claimed £22billion 'black hole' in the country's finances. 

Savers waited with bated breath to hear if Isas would be among the victims of the Chancellor's tax raid. 

It had been rumored that the £20,000 annual allowance for tax-free saving could be reduced, or a lifetime limit on Isa contributions of £500,000 imposed. 

Thankfully, that didn't happen - which is good news, as the announcements mean using a cash or stocks and shares Isa will become more vital than ever as a way of protecting your money. 

Here is what savers need to know - and some of the best Isas they can open today.  

What is the Isa allowance? 

Savers can put £20,000 per tax year into a cash or stocks and shares Isa, and the interest or profits will be shielded from tax.  

While the Chancellor didn't make any sweeping changes to Isas in the Budget, she did freeze the Isa allowance at its current level of £20,000 for a further six years, until April 2030. 

The limit for Lifetime Isas will remain at the current £4,000, and Junior Isas at £9,000, until that time. 

Savers have been calling for an increase in the £20,000 annual allowance, which will have been frozen for 13 years by 2030. 

Over the years, the real-terms value of that sum will have been dragged down by inflation. 

If the £20,000 tax-free allowance had risen each year in line with the consumer prices index measure of inflation since 2017, it would now be roughly £26,000.

How Isas can help savers

With so many taxes set to increase after yesterday's Budget, it is crucial that savers protect their money from the taxman wherever possible. 

Opening a cash Isa does just that, and it should be a key tool in anyone's financial arsenal. 

If you save money outside of an Isa and earn interest on it, you will be taxed at 40 per cent on anything above the personal savings allowance. This is £1,000 per tax year for basic-rate taxpayers and £500 for higher-rate. 

With savings rates much higher than they have been in recent years due to the effects of inflation, it is easier to breach those limits.  

Jeremy Cox, Head of Strategy at Coventry Building Society, explains: 'Unlike in previous years of ultra-low interest rates, many taxpayers with modest savings today might not even realise they could be taxed on the interest they earn.

'Unless they have shielded their savings from tax using an Isa, a higher rate taxpayer with a savings account paying 5 per cent would only need a balance of £10,000 to see their savings interest hit £500, eating up all of their Personal Savings Allowance. 

'They would have to pay the taxman 40 per cent of any further interest they received.'

Interest rates on Isa accounts are as high as 5.1 per cent at the moment. 

How Isas can help investors

The Chancellor announced major changes to capital gains tax in the Budget, meaning that basic rate taxpayers face a charge of up to 18 per cent on money made from selling shares, property or valuable possessions. 

CGT is levied on profits made when you sell investments, second properties, business assets and personal possessions worth more than £6,000, with profits above the annual tax-free allowance of £3,000 all falling within the tax net.

But crucially for investors, they can contribute up to £20,000 per year to a stocks and shares Isa, and their profits will be shielded from any tax. 

You can divide your Isa allowance across the four different types of Isas: cash, stocks and shares, innovative finance or lifetime. 

Jason Hollands, managing director of Evelyn Partners, explains: 'In a world of higher taxes, including increased capital gains tax which has risen significantly for basic rate taxpayers from 10 per cent to 18 per cent, Isas are more important than ever as a flexible, tax-efficient way to save and invest. 

'Alongside pensions they should be a core pillar of most people’s long-term savings plans. Use them while you can.' 

Laith Khalaf, head of investment analysis at AJ Bell said: 'Investments held within Isas aren’t subject to capital gains tax, nor are the dividends they produce subject to income tax. 

'A rise in capital gains tax, especially combined with an annual CGT allowance of just £3,000, means investors should prioritise pensions and Isas if they’re hoping for growth on their investments.'

Those who hold investments outside of an Isa or Sipp can perform a manoeuvre called a ‘Bed and Isa’ or ‘Bed and Sipp’ to move them inside a tax shelter. 

This does involve selling assets so there is potentially a capital gains tax liability at this point, though investors can circumnavigate this by using their annual £3,000 CGT allowance

Below are the best investing platforms, where you can open a stocks and shares Isa.