From The Times obituary 23rd April 2020 (paywalled)

"Hours before the Marine Offences Act came into effect at midnight on August 14, 1967, the pirate stations made their on-air farewells one by one — except Radio Caroline. With characteristic obstinacy, O’Rahilly continued broadcasting and resolved to go head-to-head with the BBC’s new pop station, Radio One.

When the government tried to jam Caroline’s signal, O’Rahilly visited the Palace of Westminster and accosted the prime minister. “You’re finished, son,” Wilson told O’Rahilly as he prodded him pugnaciously in the chest.

“We’ll see who’s finished,” O’Rahilly shouted back before he was escorted off the premises.

Always one to bear a grudge, he used Caroline to campaign vigorously against the Labour government in the 1970 general election. He plastered marginal seats with posters depicting Wilson as Chairman Mao, mobilised newly-franchised 18 to 21-year-olds and organised supporters to inundate the phone lines at Labour party headquarters with hoax calls."

The government didn't try to jam Caroline's signal.