Two P-platers have been busted travelling at truly unbelievable speeds on the M4 last night.

Just after 11:30pm yesterday, a red-P-plater was busted travelling over two times the legal speed limit at South Wentworthville.

The 17-year-old driver from Fairfield was doing a staggering 171km/h in an 80 zone.

He was issued with a $2435 fine, docked six demerit points and had his license suspended immediately for a period of six months.

But the stupidity didn’t end there.

Not even an hour later, police pulled over a green P-plater on the same highway doing 140km/h.

The 22-year-old South Strathfield man had his licence suspended on the spot, lost six demerit points and was issued with a fine.

Neither of the vehicles were confiscated by police.

Ray Hadley is tipping that’s because the cars aren’t registered in their names.

“We’ve got to start looking at legislation here,” he says.

“People have got to be really alert to who they give the car to, parents included.

“This kid, doing 171 in an 80 zone, could have killed himself and any number of other people.

“The other bloke doing 140 could have done exactly the same thing.”

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Images: NSW Traffic and Highway Patrol Facebook