The first winner, a man from inner London, purchased his ticket in February 2016 and invested the maximum £50,000.

The winner from Dorset won the £1m jackpot after re-investing a £25 prize won in the October 2010 draw.

The pair become the 395^th and 396^th winners of the £1m jackpot prize.

The two winning bond numbers are: 267FW537456 and 173HT264915.

Premium Bonds are offered by the government-backed National Savings & Investments (NS&I) and are the UK’s most popular savings product. Each £1 bond is entered into a monthly draw, with two lucky bondholders bagging £1m each. All Premium Bonds prizes are free of income and capital gains tax.

Jill Waters, retail director at NS&I, said: “Re-investing Premium Bond prizes can be a great way of saving and it has paid off this month for Dorset’s jackpot winner, scooping the £1 million jackpot from a £25 reinvested prize. While the London winners’ savings habit has proved particularly fruitful, winning the top prize just over two and a half years after investing.”

Customers can opt to have their prizes paid directly into their bank account, or to have their prizes automatically reinvested into their Premium Bonds account, as long as the total holding is below the maximum threshold of £50,000.

Do you have an unclaimed prize?

In the October 2018 draw, a total of 3,139,705 prizes worth £89,743,200 will be paid out.

But according to NS&I, there are over 1.5 million unclaimed prizes worth just over £60m.

In Inner London, there are over 119,000 prizes waiting to be claimed worth nearly £4.8m and in Dorset, there are over 18,000 unclaimed prizes worth £672,000.

You can check if you have an unclaimed prize waiting for you by inputting your holder’s number in the prize checker on the NS&I website. If you have lost track of your holder number, or you’re not sure whether you have any premium bonds, you can use the NS&I tracing service.

Related: See YourMoney.com’s Do your Premium Bonds die with you? for more information.