Tidal waves of nostalgia for the North Sea pirates have been flooding radio-land: an exhibition in Harwich, a glitzy West End reunion with ageing DJs and their dewy-eyed fans, a champagne party welcoming back Emperor Rosko to Britain, the jolly six-day frolic of “Pirate BBC Essex” broadcasting the original, wonderful 1960s pop music from a lightship half a mile off the coast, and coverage ranging from Johnnie Walker’s funny Radio 2 special last weekend to pieces on Today. All mark last week’s 40th anniversary of the Marine Broadcasting Offences Act, which eventually forced the pirate vessels off the air, bringing the likes of John Peel, Tony Blackburn, Ed Stewart and (later) Johnnie Walker into the BBC, with the creation of Radio 1.

If you remember Caroline, Shivering Sands, Big L and the Perfumed Garden, then you probably remember what it was like to be young in the 1960s, and this month has evoked much of its heady excitement. All the same, there are dangers in romanticising unlicensed radio, whether now or then. Harold Wilson’s government claimed that the pirate ships, despite providing a service of all-day pop for which there was clearly a huge demand, endangered ship-to-shore transmissions. The point remains valid today, even if today’s illicit DJs are urban rather than maritime.

“Pirate radio stations can cause interference to safety-of-life services such as the fire brigade and air-traffic control,” says the regulator, Ofcom. “We conducted more than 1,000 raids against illegal broadcasters last year and secured 63 convictions.” Andrew Harrison, boss of the trade body RadioCentre, says that, in addition to disrupting emergency services, today’s pirates “drown out legitimate stations, denying listeners the station of their choice, pay no tax and put lives at risk by tapping into high-voltage power supplies from communal lifts”.

It seems perfectly possible to accept those arguments – and my Radio 3 reception certainly suffers from the propinquity of an illicit reggae neighbour – while recognising that the pirate stations have done much to widen listener choice. The North Sea pirates (the first of which was begun by a young Irish music producer called Ronan O’Rahilly, when he could not get his Georgie Fame record played on the Light Programme) championed Stax, Tamla Motown and Atlantic soul, which until then had received little airtime.

Today’s pirates play more esoteric varieties of black music, also marginalised by the mainstream. But it was the pirates who operated between these two periods, the ones associated with the 1980s, who contributed the most.

Xfm, for example, began life as an illegal station (called Q102), as did both Kiss FM and London Greek Radio. Sunrise Radio – run by the Asian entrepreneur Avtar Lit, whose son Tony recently hit the headlines when he went from Labour donor to Tory by-election candidate in five days – likewise began as a pirate, in Hounslow. All of those are now legitimate and have given much pleasure and community spirit to different groups of listeners, but all began in the knowledge that they were breaking the Wireless Telegraphy Act. The paradox is that pirates have greatly benefited the airwaves, while also making them more dangerous.

paul.donovan@sunday-times.co.uk

Editor's choice

• Exclusive: Listen to AC/DC's Black Ice
• Burning Bush with W
• Boy George on sex, drugs and Amy Winehouse