Rear Window: How Quintin Hogg made sure the kids were all right: Loud rock concerts

THE NOTE from Mick Jagger read: 'Dear Charlie, Thank you, thank you, thank you. They say you could hear it in Edgware]'

The sound that could be heard in the London suburb of Edgware one summer's day in July 1969 had come all the way from a stage in Hyde Park, where the Rolling Stones gave a famous free concert before an estimated audience of 300,000. The Charlie to whom Jagger was grateful was Charlie Watkins, the sound equipment engineer whose state- of-the-art 1,500-watt public address system had projected Jagger's voice clear across the capital.

By modern standards 1,500 watts is something of a whisper: when the Rolling Stones open the American leg of their latest world tour tomorrow at the RFK Stadium in Washington DC, they will be employing a system capable of 1.5 million watts. Yet in 1969 Charlie Watkins's system at Hyde Park was regarded as astonishingly powerful, and just a couple of years before a mere 1,000 watts had been loud enough to land him in serious trouble.

The incident happened during the National Jazz, Pop, Ballads and Blues Festival in August 1967 on Windsor Racecourse, where Watkins set up the first 1,000-watt live music public address system - and was promptly taken to court for it.

The effective difference in loudness, then compared to now, is not quite as dramatic as figures suggest - wattage must be increased approximately tenfold in order to double volume - but even so, Watkins's system was far too powerful for the good people of Windsor.

By day two of the festival, residents and local officials had had enough. As Arthur Brown unforgettably dramatised his song 'Fire' by igniting his own hair whilst on stage, an unimpressed local deputation filed past the smouldering pop star. Among them were the Lord Mayor, representatives from the Noise Abatement Society and a police inspector, who promptly confronted Watkins, still seated at his soundboard below the stage.

Politely but firmly the inspector asked the sound engineer to accompany him to the police station. Watkins said he was ready to comply but pointed out that he would have to switch off the public address system and asked: 'What are you going to do with thirty or forty thousand hippies who have nothing better to do than go ranging around Windsor for the next two days?'

His point was taken - and the show allowed to go on for a further day and a half - but the matter did not end there.

A furious Windsor council decided to seek an injunction banning the festival, an annual event, from returning to the site ever again. Summonses were issued both to Watkins Electric Music (WEM) and the organisers, Marquee Promotions, to appear before magistrates at Reading County Court in September.

Harold Pendleton's (Marquee Promotions) choice of legal representation in this, a test case for all subsequent outdoor festivals, was inspired: Lord Hailsham, then the formidable barrister Quintin Hogg, a former Conservative Party Chairman and Minister of Science.

In court Watkins and his designer, Norman Sargent, gave evidence for the defence, while the brunt of Windsor council's case against 1,000 watts was put to magistrates by a scientist from Reading University.

Under determined cross-examination by a former science minister, this young academic began to encounter difficulties, and in the course of one rather general technical answer, he was dismayed to be pulled up with the booming question: 'Are you trying to be tricky with me, sir?'

The decisive moment came later in the proceedings, when Watkins was asked by the registrar if anything could be done to deflect the sound away from nearby residents' houses, and declared firmly that a marquee tent should be erected 100 yards from the stage, and this would have the effect of directing most of the sound upward toward the heavens.

The authority with which this essentially fatuous suggestion was delivered allayed the registrar's remaining doubts, and with that the case was dismissed.

Nowadays, hi-tech decibel meters and precise EC directives on maximum permissible noise levels do the job of the Windsor police inspector. Live music at rock venues such as Wembley Stadium is closely monitored, and all concerts there now take place with Brent council's blessing.

Tomorrow at the RFK Stadium the Rolling Stones will in theory be up to eight times as loud as at Hyde Park in 1969 - but with vastly improved sound quality and, crucially, minimal distortion. For this, in a small way, Mick Jagger may owe thanks not only to Charlie Watkins, but to Lord Hailsham.

(Photograph omitted)