What is the ideal portfolio for a stocks and shares ISA? Some investors prefer the perceived safety of bonds, others place their trust in dynamic fund managers.

If, like me, you have the time and inclination to do your due diligence, you probably prefer individual stocks. In addition to the possibility of obtaining above-average profits, individual stock selection gives me a sense of control over my own fate.

With this in mind, here are three leading UK shares to consider when creating a pensions-focused ISA.

RELAX

RELAX is an ideal UK long-term pension holding as it provides stability with recurring subscription revenue (over 50% of revenue), high margins and exceptional free cash flow of ~27% of revenue.

The company increased its net profit by 8.59% year over year, maintains a net profit margin of 20.5% and has increased its dividend for 15 years in a row. Dividend growth is typically in the high single digits, with a payout ratio of around 62%.

With ₹2.59b of annual free cash flow and ₹2.61b of operating cash flow, debt appears manageable, if a bit high.

A more pressing risk is the threat of disruption from generative AI, which could change the way professionals access information.

AstraZeneca

AstraZeneca (LSE: AZN) is another standout long-term retirement holding worth considering. It provides exceptional stability with a diversified portfolio of oncology-focused drugs, powerful cash flow generation and a disciplined balance sheet.

The company reported 2025 revenues of £46.3 billion (up 8%), with fourth quarter 2025 revenues up 4% to £12.2 billion. Looking ahead to fiscal 2026, the pharma giant anticipates mid-to-high-single-digit growth in total revenue and low-double-digit growth in core EPS.

Dividend give that’s not much – just 1.73%, but a payout ratio of just 46% creates room for growth. Its balance sheet shows total assets of £82.3 billion against liabilities of £50.5 billion, demonstrating its financial resilience.

The key risk is the expiration of patents, among others To Farhi (annual sales worth £6 billion) has lost exclusivity, which could put pressure on revenues if pipeline roll-outs fail to offset the decline.

Diploma

Diploma (LSE: DPLM) offers exceptional stability with diversified exposure to three core industries: life sciences, industrial control and security. It enjoys powerful cash generation and implements disciplined capital allocation.

The company reported powerful results for FY25, with revenue up 11% to £1,524.5m and adjusted operating profit up 20% to £342.7m. It also has excellent operating margins of around 22.5%. Free cash flow was GBP 247.2 million at 105% conversion, while leverage is conservative at 0.8 times net debt/EVENTS.

Like AstraZeneca, it is a growth-oriented company generating a low dividend yield of 1.1%. However, with a payout ratio of just 43.85% and an average dividend growth of 10.78% over three years, it shows promise.

The key risk is integration and acquisition execution, as Diploma’s growth strategy is based on both organic growth and selective acquisitions in competitive markets.

Final thoughts

When looking for stocks that can be held for a decade or more, it’s significant to look beyond headline growth and earnings numbers. It is unlikely that a company that has grown 100% in a year will maintain this momentum indefinitely. Stocks with a 9% yield are likely undercovered and will soon need to reduce payments.

Instead, focus on things like diversified income streams, earnings visibility, and recurring revenue. The three listed here meet these criteria, but they don’t stand alone – there are plenty of other equally attractive options on the UK market to consider.

Is it worth investing £5,000 in AstraZeneca Plc now?

If investing expert Mark Rogers and his team have stock advice, it can pay to listen. After all, Twelfth Magpie’s flagship Share Advisor newsletter, which it has run for almost a decade, provides thousands of paying members with the best share recommendations from across the UK and US markets.

Mark believes there are 6 standout stocks that investors should consider buying right now. Want to check if AstraZeneca Plc is on the list?

Mark Hartley owns shares in AstraZeneca, RELX and a diploma.