The yearly Stocks and Shares ISA allowance gives UK investors a powerful way to build a largely tax-free passive income by regularly investing. The key attraction being that investors can enjoy all capital gains and dividends without attracting any tax liability.

In an environment of rising taxes and persistent inflation, fully utilising the £20,000 ISA allowance has become essential for those aiming to achieve financial freedom. So let’s explore how a new investor can begin building a reliable, lifelong income stream.

Please note that tax treatment depends on the individual circumstances of each client and may be subject to change in future. The content in this article is provided for information purposes only. It is not intended to be, neither does it constitute, any form of tax advice. Readers are responsible for carrying out their own due diligence and for obtaining professional advice before making any investment decisions.

Take a realistic approach

Of course, the idea of getting rich quickly is appealing. But in the stock market, building wealth seldom happens overnight. Before you even begin, accept that it’ll likely take a long time and lots of dedication.

The most popular (and proven) approach is to invest in high-quality assets for the long term and allow regular contributions to compound the pot.

So even with £20,000 invested from the outset, the initial passive income won’t be mindblowing. Using the recommended 4% withdrawal rule as a guide, it would only equate to roughly £800 a year.

Ok, but how could that eventually grow over time? 

Average calculations

Let’s assume you pick decent stocks and achieve slightly above-average market growth of around 9%. If left for 10 years, that pot would grow to over £49,000. Another 10 and it’s over £120,000.

Still, that’s only £4,800 a year at the 4% drawdown rule. But if you used the full £20,000 allowance each year, it would grow to a massive £1,188,153. Now, the 4% rule equates to £47,526 – almost £4,000 a month.

Admittedly, not many people can afford to invest £20,000 a year. So naturally, the final amount will differ depending on individual financial circumstances.

The key is to start as early as possible and be disciplined.

Hunting top stocks

The real question is which stocks to consider. One candidate that’s worth investigating further is Primary Health Properties (LSE: PHP). The real estate invetment trust (REIT) manages healthcare facilities such as GP surgeries and pharmacies.

Since REIT rents come directly or indirectly from public-sector bodies, cash flows are usually more stable than in many other property sectors. This stability adds attraction when aiming for long-term income.

Currently trading at 93p per share, the average 12-month price target of 114p suggests a potential 22.3% price rise.

But the real attraction here is the regulated shareholder returns that REITs must honour. The scheme enjoys tax benefits in exchange for ensuring 90% of profits go back to shareholders as dividends. That’s why the stock enjoys an attractive 7.82% yield backed by a 29-year-long payment track record.

Final thoughts

Regulated or not, Primary Health is still exposed to interest-rate sensitivity, property valuation changes, and political shifts affecting healthcare funding. Even if dividends remain strong, the price could underperform if financing costs rise or if investor sentiment toward property weakens.

As such, it’s worth considering but only as part of a diversified portfolio of growth and defensive stocks. This helps reduce volatility while ensuring stable, sustainable growth.

A few promising options I’ve looked into recently include 3i Group, Tesco and National Grid — but there are many more to consider.