Officers received lots of calls from worried motorists who spotted the elderly man.
He was cycling west on the eastbound carriageway of the M4.
Police stopped the man just past junction 5 and escorted him off the motorway in a police car, at 11.10am today.
Mini bus driver Tracey Smith said: "He was cycling along the hard shoulder - against the traffic.
"I couldn't believe it. I had to pull over and call the police."
She described the man as Chinese and wearing a pink helmet.
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