Dawn at Malaga airport and the first bleary-eyed passengers struggle off the early charter flights from Britain. Some are holidaymakers heading for the beaches, golf courses and Robin Hood pubs of Spain’s Costa del Sol. But at this hour, most are homebuyers. Clutching brochures with jaunty “Live the dream!” slogans, they want to make the most of their weekend search for a place in the sun.

Waiting for them outside the terminal building are fleets of cars — blue minibuses for ordinary buyers and silver BMWs for well-heeled private investors. Grey-suited girls, sweating in the heat, smile and wave: “This way for Ocean Estates!” With cash in their back pockets and hope in their hearts, dozens of prospective buyers climb into the air-conditioned cars and head off into a brighter future.

One woman, however, is not smiling. Wearing jeans, sandals and a pink T-shirt, Haley Neaves watches the scene with a mixture of pity, contempt and shame. “They are lambs to the slaughter,” she says as the BMWs and minibuses head for the autopista to Marbella and beyond. “They think their lives are about to get a whole lot better. But the chances are they’ll end up worse off.”

Neaves should know. For two years, the 23-year-old from Hampshire lured planeloads of property investors out to southern Spain and helped sell them hundreds of holiday homes. She worked for one of the biggest estate agents in the area, Ocean Estates, but quit this summer because she felt that her firm — like others in southern Spain, she says — was ripping off unsuspecting investors.

Neaves’s story should be read by anybody considering buying property on the Costa del Sol or the Costa Blanca. She exposes the ruthless tactics that some of the biggest overseas property firms use to tempt naive British buyers into parting with hundreds of thousands of pounds. In an exclusive interview with The Sunday Times, she reveals how estate agents lure purchasers by promising that investments are “risk-free”.

Neaves joined Ocean Estates after moving to Spain two years ago. The firm is run by Alasdair and Alice Macdonald, a British husband-and-wife team, and is based in Puerto Banus on the Costa del Sol but also operates in South Africa and Asia. Its slogan is: “Your investment is secured, your dream awaits.”

Neaves worked in the company’s Costa Blanca office in Alicante, starting as a receptionist before being promoted to join the sales team. Her job was to tempt potential British buyers to sign up over the phone for “inspection weekends”: three-day property viewing trips to the Costa del Sol and the Costa Blanca. Once they arrived, she had to persuade them to buy.

“It was ‘sell, sell, sell’ all the time,” she recalls. “The managers would tell us: ‘Don’t think of the punters as people. They are just money’. The whole atmosphere was intimidating. Managers screamed at us the whole time to work harder. It was ‘sell or get sacked’. I’m ashamed to say I decided to sell.”

Neaves used every trick in the book to identify potential buyers, to persuade them to come to view properties and to make them put down deposits on new homes, ringing potential clients relentlessly, at 8 o’clock on Sunday morning or even when they had asked her not to keep calling. “I was sneaky and underhand. I lied and scammed every time a buyer phoned up or signed up at one of our UK property exhibitions.”

She followed a set sales technique. Neaves started by weeding out buyers too poor to bother with. “When I started chatting on the phone to a buyer, I innocently took their postcode. While they were on the line I went to the internet site upmystreet.co.uk to check the average property band in their area. If the average house was worth less than £80,000, I hung up.”

Once she had identified potential buyers with money, Neaves targeted their children. “If I knew someone was wealthy and might want to invest, I telephoned them after school hours. If a child answered the phone, I asked whether they were happy at school in England and had lots of friends or whether they would rather go to school in Spain where it was ‘nice and sunny’. When their parents came on the line I would say something like ‘even your daughter wants to come over here’.”

One common sales technique was known as “hands-free”. If Neaves was struggling to persuade a buyer to come to Spain to view properties, she put the caller on hold. “While the buyer was waiting, I would go into the boardroom, pick up the call again and put it on speakerphone, so my manager could sit in with me and listen. Each time the buyer raised a problem, the manager would hold up a card with the answer I should give.

“If a woman said her husband had just died he would hold up a sign saying: ‘Chance for a fresh start!’. If someone said they were getting divorced, a sign would say: ‘Lots of attractive, outgoing single people here!’. At the end of every call a sign appeared saying: ‘Come and live your dream!’ It was cynical and manipulative but most of the time it worked, and people agreed to come out on viewing weekends.”

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