Auto-enrolment is not a fatwa
UK law puts most employees into a workplace pension. Opting out throws away employer match — real money. The default fund is almost never Shariah-compliant. That is the whole problem.
NEST, HSBC, Legal & General, Aviva and others offer a Shariah or Islamic global equity option in many schemes. Log in, find “change fund”, pick it. If your scheme has nothing, ask HR in writing; some will add a fund if enough people ask. Opting out to avoid riba, then saving the same amount in a screened ISA, is a position some scholars prefer when a Shariah fund truly does not exist.
ISAs and SIPPs
A stocks-and-shares ISA is a tax wrapper, not a product. What you hold inside it is the issue. Cash ISAs pay interest: that coupon is riba; the wrapper does not wash it. A Shariah-compliant fund or screened shares inside an ISA is the usual UK route for taxable accounts.
A SIPP lets you hold sukuk, Islamic funds, and sometimes direct property. Fees are higher. It is a tool for people who will actually operate a screen, not a default.
Zakat on pensions
If the pot is locked until a legally defined age, a widely used view is that zakat is not due on it until you can access it (then on the zakatable portion). Another view calculates annually on your vested rights. Choose one with a scholar who knows your scheme, and stay put.