Members of a religious sect linked to a constituency Conservative party are alleged to have taken tithes, fees and insurance totalling up to £2,000 a month from families in their congregation.
One married couple was persuaded to take out up to 14 insurance policies covering everything from endowments on their home to critical illness injury cover from companies run by pastors of the church, it is claimed.
When an archbishop of the church visited, families were asked to give an additional "love offering" of up to £2,000.
A young mother is suing 12 members of the Peniel Pentecostal Church in Essex, including her former husband, seeking £160,000 in compensation. Caroline Green, 33, accuses the church of brainwashing, undue influence and mis-selling insurance policies. She also alleges that church members beat her children.
The church has also been accused of attempting to infiltrate and take control of Brentwood and Ongar Conservative party. More than 100 members joined a local Tory association after the sect had its planning application for a school sports hall turned down.
The presence of the sect has persuaded Martin Bell, the independent MP for Tatton and former BBC reporter, to stand as a candidate against Eric Pickles, the sitting Tory MP, at the general election. Green was first sent, aged 14, by her parents to a boarding school run by the church. At the age of 18 she was persuaded to marry the 20-year-old son of a founder of the church and had three children with him.
The church's bishop, Michael Reid, a former policeman, has told his 800-strong congregation they cannot "out-give God". Most of the congregation live within a few miles of Reid's home and the church and are asked to attend up to four services a week, each lasting up to three hours.
Green claims her husband had to surrender a tithe to the church every month of £600 from his earnings. The couple paid monthly school fees for the children to the church. The insurance policies cost £1,200 a month, with the commissions going to senior church members.
Green, who is now studying to be a nurse, said: "We were financially drained. When the penny eventually dropped and I realised this did not represent Christianity, the church got my husband to divorce me on the grounds of unreasonable behaviour.
"This included falling asleep on Christmas afternoon and leaving a party too early. "I eventually left the area with my children, a suitcase and £5 in my purse." She has written to Elizabeth Filkin, the parliamentary standards commissioner, complaining about the influence the church has on the Tory party in the Brentwood and Ongar constituency.
Anne Brown, a deaconess of the church who acts as its spokesman, denied all Green's claims. She said the church itself had no political links. "We would love to bring this matter before a judge and put it to death," she said. "We are very confident there is no merit whatsoever in these insidious allegations."