Sir Paul McCartney used Heather Mills’ artificial leg to smuggle marijuana, actor Denis Leary has jokingly claimed.

The ‘Rescue Me’ actor launched the attack against The Beatles legend and his ex-wife – who has an artificial leg following a motorcycle accident in 1993 - in his new book ‘Why We Suck: A Feel-Good Guide to Staying Fat, Loud, Lazy and Stupid’.

He wrote: “Heather Mills must have given great h**d. Plus, he's a big pothead so he probably figured the fake leg would come in handy for smuggling marijuana.”

Denis, 51, has also attacked children diagnosed with brain disorder autism, calling them “dumb-a** kids”.

He wrote: “There is a huge boom in autism right now because inattentive mothers and competitive dads want an explanation for why their dumb-a** kids can't compete academically, so they throw money into the happy laps of shrinks to get back diagnoses that help explain away the deficiencies of their junior morons.

“I don't give a f**k what these crackerjack whack jobs tell you - your kid is NOT autistic. He's just stupid. Or lazy. Or both."

His comments have outraged children’s organisations, with The Autism Society of America responding "For Mr. Leary to suggest that families or doctors conspire to falsely diagnose autism is ridiculous.

“His remarks reflect the same misconceptions of autism being caused by bad or unemotional parenting that were held over 50 years ago.”