Only 11 immigrants volunteered to leave Britain after seeing the Government's now-scrapped "go home" vans, an evaluation report has revealed.
The broader pilot, which also included postcards in shop windows and adverts in newspapers, led to 60 voluntary departures. A further 65 cases are currently being progressed to departure.
In addition, the report reveals the phone number used in the near £10,000 campaign, dubbed Operation Vaken, received a total of 1,561 text messages - but 1,034 were hoaxes.
Around 17 hours of Home Office staff time were required to deal with the hoax messages, the report added.
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Officers were called to Stoke Newington High Street were they found the road littered with items.
Dry and cloudy tonight. Breezy at times. Lows of 9C.
The Commons Environmental Audit Committee warned ministers not to approve the scheme unless the airport gives assurances about air quality.