The parents of a 28-year-old British woman missing in Pakistan have appealed for her safe return, and said they feared Pakistani acquaintances may have lured their vulnerable daughter into danger. Leah Reed, who needs medication for bipolar disorder, told her family she was leaving on a domestic holiday on April 24 but has not been seen since. Police have traced her passport and found she travelled from Heathrow to the Pakistani city of Lahore, said Leonard Reed, her father, a retired teacher with terminal cancer. He now fears her vulnerable state may have seen her duped into the sex industry, the drugs trade or that she may be forced into marriage. However, he said attention was focused on her \"Pakistan connections\" but that he could not discuss the case for fear of jeopardising police action. \"The crucial happenings are occurring as we speak,\" he told The Daily Telegraph from his home in Cambridgeshire. He added that he was hopeful of a speedy rescue even though Pakistan\'s population of 180m made it more difficult to find missing people. \"It\'s a larger place than Great Britain with larger difficulties for fishing someone out – although it\'s a wonderful country I\'m sure,\" he said. Earlier, he said he feared his daughter\'s reliance on lithium to manage her illness meant police faced a race against time. \"It seems practically certain that our daughter has been targeted, being seen as extremely vulnerable, for some nefarious, as yet unknown purpose,\" he said. He and his wife, Asta, who have nine children, have been in close contact with police and the British High Commission in Pakistan. Mrs Reed told The Cambridge News: \"I have been overwhelmed by the support we have had from people close to us and from the police, which is all helping. \"I want to say \'hang on, you will be found\' to Leah because I know she is having a horrible time.\" Pakistan has a reputation as a human trafficking and drug smuggling hub. A British woman, Khadija Shah, was arrested on Sunday as she tried to board a flight from Islamabad to Birmingham carrying about 140 pounds of heroin. And the Foreign Office has a Forced Marriage Unit, which is active in Pakistan rescuing young women – and sometimes young men – who have been brought from the UK to marry in their parents\' or grandparents\' homeland. A spokesman for the British High Commission in Islamabad said consular staff were aware of reports of a missing Briton. \"We are looking into this and stand ready to provide consular assistance,\" he said.