Should we change our MINI's 11-year-old tyres?

Our MINI Cooper is 11 years old and still running on its original rear tyres that have 5mm of tread remaining. The tyres are 15-inch Dunlop SP Sport and have covered 39,000 miles. In your opinion should the tyres be replaced due to age?

Asked on 5 October 2013 by DH, via email

Answered by Honest John
Without a shadow of a doubt.
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