What is an expression of wish?
An expression of wish tells pension scheme trustees who you would like to receive your death benefits. It is not legally binding and it is not governed by your will — which is exactly why an out-of-date nomination can send a lifetime's pension to a former partner.
Trustees retain discretion, and that discretion is the mechanism that has kept pension death benefits outside the estate for inheritance tax. They will normally follow a current nomination; they are not obliged to, and they will look at present circumstances.
There is one per scheme. Someone with five pensions from five employers has five nomination forms, and completing one does nothing for the other four. The will has no effect on any of them.
It should be reviewed on marriage, divorce, a birth, a death, or a change of relationship — none of which prompts it. Of everything in this glossary, an unreviewed nomination is the single most common, most consequential and most easily fixed gap in an otherwise well-organised estate. The April 2027 inheritance tax change raises the stakes further.