In the past five weeks 2,500 attempts have been made to hack into private data at the abortion provider The British Pregnancy Advisory Service (BPAS), according to a BBC report. Though none of these attempts was successful, they will have left women in need of advice and feeling scared, intimidated and uncertain who to turn to.

The revelation comes hot on the heels of the conviction of James Jeffery who was jailed last month for stealing details of 10,000 people who had contacted BPAS for advice. No medical records were compromised but the data Jeffery succeeded in hacking was names and emails of people who had contacted the service. Some of them were probably trying to sell them double glazing.

There have always been people in our society who oppose abortion. For many it is part of a personal religious belief. They would prefer not to choose that option for themselves (though some abortions are life-saving procedures), but they respect that others have different views and a right to choose for themselves.

Others are actively seeking a rolling-back of the law to pre-1967 conditions. They will be forever locked in a battle with those who remember the horrors of unsafe backstreet abortions from the 40s and 50s, but still they are entitled to their view, to write to their MP about it, to protest outside parliament, sign petitions and so on. However, a tiny but highly motivated minority exercise their opposition to abortion in a much more extreme way. Groups like 40 Days for Life and Abort67 have recently taken to protesting on the street outside abortion clinics, taking film footage and photographs and distributing misleading information. A rape victim in Brighton bravely came forward and described feeling judged and harassed as she attempted to go in for a medical appointment to discuss her unwanted pregnancy.

These groups often have links to evangelical extremist churches and similar groups in the US. The hacking revelations also show that many of the failed attempts may have originated in America. If they didn't, the tactics they're using certainly came from the US, and most likely the funding too.

Extremist groups like these can be intimidating, but what is most worrying is when they appear to be infiltrating the mainstream. The charity Christian Action Research and Education (Care) has funded interns working with 20 MPs including the environment secretary Caroline Spelman. It hit the headlines recently sponsoring a conference arguing that homosexuality could be "cured", it is also profoundly anti-choice.

In Bloomsbury Square the recent 40 Days for Life protest ended with the Catholic bishop of Westminster holding a prayer meeting. To see a senior member of a major church supporting a protest that had included the harassment of individual women was utterly sickening.

Sadly, the tactic seems to be working. Recent statements by the health secretary, Andrew Lansley, have made it clear that the small but vocal anti-choice movement has his ear. The Department of Health is planning changes that will give groups like Life and Care Confidential, ideologically opposed to abortion, an official role in counselling women in crisis pregnancy, funded by public money that could instead be spent on providing actual healthcare.

One in three women in the UK has had an abortion. Women you know have had an abortion, lots of them. I've had an abortion. We don't go round broadcasting it from the rooftops. Firstly, because it's a private medical procedure; I've also had a colposcopy and a biopsy on a breast lump that turned out to be nothing much and went away shortly afterwards. But all of this is none of anybody's business unless I choose to tell them.

Secondly we don't tend to go public about it because we know there are people out there who will take that information and use it as grounds to harass us, to threaten us and to compromise our day-to-day lives. The conversation about abortion needs to be full and frank and informative. It also needs to be private. Between a woman and the doctor and trained medical staff who are treating her.

The UK does not have anywhere like the level of extremist religious and evangelical groups the US has. Those who respect a woman's right to choose on abortion remain the vast majority in the UK. We must not allow the US's rightwing misogynist agenda to infiltrate our mainstream and threaten the privacy and security of individual women.

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