There is piece of legislation called statute barred. This refers to the Limitations Act.
This is the only real piece of debt law that could see your debt deemed unenforceable, after a period of six years.
Creditors are unable to legally pursue you for the debt if, after six years;
The creditor has not already obtained a county court judgment (CCJ)
You or any one else owing the money (on a debt in joint names) have not made a payment
You have not written to the creditor admitting you owe the debt
- See more at:
http://moneyaware.co.uk/2011/08/your-debts-written-off-is-it-too-good-to-be-true/#sthash.2JId450r.dpuf