It was a phone call from out of a parents’ nightmare. A hoarse voice on the other end whispered: “We have your daughter and we will kill her.”

Gunmen who snatched a three-year-old British girl, Margaret Hill, on her way to school in the Nigerian oil city of Port Harcourt in the volatile south of the country on Thursday contacted the family early yesterday.

Her distraught mother, Oluchi Hill, a Nigerian national married to Mike Hill, a Briton from North East England, told local journalists that the kidnappers said they were feeding her only bread and water.

The voice on the other end of the line then gave warning that the child would be killed unless the father came and took her place.

“They say I can bring my husband to swap with the baby,” Mrs Hill told the BBC in a short interview. She added that she was able to talk briefly to Margaret, who was crying. Later, she told the French news agency, AFP: “They have not made any demand. We are still waiting for developments.”

A few hours later the family pleaded to be left alone while the authorities stepped up efforts to secure the girl’s release. All efforts to contact the family were referred to the British High Commission in Abuja, the Nigerian capital.

The Foreign Office issued a statement on the family’s behalf, which said: “You are well aware of the effects that this terrible situation will be having on us as a family. Everybody is trying to help us get our daughter back. We are very grateful for their support and ask the media to please leave us to work with others to try and bring our daughter home safely and quickly.”

Sources in Port Harcourt said that other than the trauma of being kidnapped at gunpoint by masked men, they did not believe the girl was in real danger.

“Contact has been made with the kidnappers, I imagine negotiations over a ransom and possible immunity are at an advanced stage now – hence the blackout,” said one well-informed source in the city. Police declined to comment on the situation.

Meanwhile, in a positive development for the family, the main militant group in the oil-rich Delta region, the Movement for the Emancipation of the Niger Delta (MEND), which is responsible for a spate of kidnappings of foreign oil workers, distanced itself from the abduction and said it would help obtain her release.

Before the news blackout, Mrs Hill said that the kidnappers had told her to meet them in a town in neighbouring Bayelsa state, but that neither she nor the police had been able to find out where it was.

Mr Hill, who has lived in Nigeria for 10 years, is originally from Murton in Co Durham. He is not employed by one of the major oil companies, but instead runs a well-known bar in the city, called Goodfellas – until recently a popular venue of foreign oil workers nicknamed “Goodies”. He also works as a contractor for an oil-supply company, Lone Star, contracted by Royal Dutch Shell to run some of its offshore rigs. One of these was attacked on Wednesday and five expatriate workers were taken hostage. It is not clear whether the two incidents are linked.

The Foreign Office said: “High Commission officials are in contact with the Nigerian authorities. We call for her immediate safe release.”

It was unclear who was behind the kidnapping, but criminal gangs often linked to militant separatists are usually to blame for such incidents. They recently kidnapped two children of wealthy Nigerians who were later released unharmed. It is presumed a ransom was paid, but this is the first case of the daughter of a foreigner being

targeted. “This is entrepreneurial kidnapping of the type you used to see in Colombia or Mexico. The girl will not be in serious danger, but it is a very disturbing new game in town,” an expatriate resident in the city said.

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