Privacy lawyer Gerald Shamash has told the Guardian that the allegations a Virgin Atlantic employee passed on information about eight celebrities is "extremely worrying" and "this could be the tip of the iceberg".
Mr Shamash also said advance knowledge of the whereabouts of celebrities was the "bread and butter" of life as a picture agency or tabloid newspaper.
"Once it has these details, the agency does one or two things: it keeps [the information] to sell it or phones a newspaper to say this person has gone to Los Angeles. It's a symbiotic relationship with newspapers."
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Police are trying to find the driver of the car following the incident in Kingfisher Close, Brownhills.
An unnamed man died at the scene, while a woman was pronounced dead after being taken to St George's Hospital, Tooting, south-west London.
Eastern areas will see a few showers coming in on the northeasterly breeze