A Stocks and Shares ISA passive income of £15,815 a year could flow from a single £20,000 investment, based on a decade of average platform returns and a 5% income yield, illustrating why the tax wrapper remains one of the most powerful tools available to UK retail investors.
UK adults can shelter up to £20,000 a year inside a Stocks and Shares ISA. All returns, whether from dividends, capital gains, or interest, are entirely free of tax for life.
How a single £20k allowance compounds over 30 years
Over the last decade, the average Stocks and Shares ISA has grown at an annual rate of 9.64%, according to Unbiased. Apply that rate to a £20,000 lump sum left untouched for 30 years and the pot reaches £316,301, of which £296,301 represents growth on the original capital.
That figure is not guaranteed. Returns could be lower, or indeed higher, depending on markets and how the money is invested. Dividend reinvestment, compounding those payouts back into more shares, is what drives the bulk of long-run equity returns.
At a 5% income yield, a £316,301 pot produces £15,815 a year. That income should also grow over time, as companies raise their dividends annually.
British American Tobacco and the Stocks and Shares ISA case study
British American Tobacco (LSE: BATS) is among the FTSE 100 stocks frequently cited in this context. The company has raised its dividend for 28 consecutive years. Its shares have risen roughly 75% over the past five years and around 15% over the past 12 months.
On 12 February 2026, British American Tobacco’s investor relations announced an interim dividend of 245.04p per ordinary share for the year ended 31 December 2025, payable in four equal quarterly instalments of 61.26p in May 2026, August 2026, November 2026 and February 2027.
Fidelity’s dividend history for the stock shows the company’s dividend per share has grown from 2.1780p in 2022 to 2.4024p in 2025, with a projected 2.4504p in 2026. The 2025 payout ratio stood at 170.77% of earnings, reflecting the gap between reported net income and the company’s commitment to maintaining its progressive dividend.
According to Hargreaves Lansdown, the company reported 2025 full-year revenue of £25.61bn and net debt of £30.62bn, a figure investors in the stock need to weigh alongside the income appeal.
British American Tobacco’s Half-Year Report for the six months to 30 June 2025 disclosed an increase in its 2025 share buy-back programme by £200 million to £1.1 billion, and set a medium-term target of approximately £50 billion of free cash flow before dividends between 2024 and 2030.
Tobacco stocks carry risks that other dividend payers do not. Smoking rates continue to fall, the sector faces class action litigation, and regulatory pressure on vaping is rising. Those considerations make British American Tobacco a stock to hold within a diversified portfolio rather than in isolation.
ISA allowance changes from April 2027
The annual Stocks and Shares ISA allowance of £20,000 is set to remain unchanged, but savers should note that the broader ISA landscape is shifting. From 6 April 2027, the UK government will reduce the Cash ISA allowance to £12,000 for savers under 65; those aged 65 and over will retain a £20,000 Cash ISA limit.
The change does not affect the Stocks and Shares ISA limit, but it will redirect more of the available ISA headroom toward equities for younger savers who currently split contributions between both products.
The critical variable for long-run wealth accumulation remains time in the market. A 30-year holding period, with dividends reinvested throughout, is what turns £20,000 into a six-figure sum. Whether British American Tobacco or another dividend payer provides the engine, the ISA wrapper ensures the tax authority takes none of the proceeds.
The next test for British American Tobacco’s dividend commitment comes in May 2026, when the first of the four quarterly instalments declared in February falls due.
