Ever tossed aside loose change without thinking twice? One particular British coin may make you wish you hadn't, with the potential to fetch a hefty sum. Such a remarkable coin is none other than ...

And its worth has been on an upward trajectory. This coin was sold for £40,000 in 2004 and rose to £45,000 within just two years. READ MORE: New Turkey travel advice issued as British tourists told ...

The coin sold for $18.9m and the plate block for ... Despite it carrying a $10m lower estimate, British stamp dealer Stanley Gibbons swooped in and snapped it up for $8.3m (£6.1m).