Simon Read: If you've got premium bonds it's time to check them

Do you have £25 worth of Premium Bonds and live in London? You could be owed £100,000!

You also need to be a woman – there's one female Londoner out there who is yet to claim a £100,000 prize according to National Savings & Investments (NS&I).

The Londoner won in February 2007 but NS&I has been unable to contact her, possibly because she's moved home. The Government agency is stepping up efforts to contact some 898,000 winners who have not yet claimed prizes.

There is no deadline for winners, so prizes can be claimed at any time. In fact the oldest unclaimed prize dates back more than half a century to November 1957 when a South Yorkshire man won £25.

There are £44m worth of prizes waiting to be claimed. Jill Waters of NS&I, said: "Prizes often become unclaimed when people move house, or forget that bonds have been bought for them as a child."

You can check whether you are a winner at nsandi.com.