The Charity Commission guidance on political activity could hardly be clearer: "A charity must not give support or funding to a political party, nor to a candidate or politician." Our report today that Care, the Christian charity, has been paying the salaries of research assistants for at least eight MPs appears on the face of it to suggest that the law has been broken.

The Charity Commission guidance on political activity could hardly be clearer: "A charity must not give support or funding to a political party, nor to a candidate or politician." Our report today that Care, the Christian charity, has been paying the salaries of research assistants for at least eight MPs appears on the face of it to suggest that the law has been broken.

Many people will feel instinctively uneasy about Care's tactics in campaigning against provisions of the Human Fertilisation and Embryology Bill. But it is important to be clear what it is about the campaign that is objectionable and what is merely the advocacy of positions with which the rationalist majority disagrees. Care, which stands for Christian Action, Research and Education, shares many of the characteristics of – indeed, it explicitly models itself on – the religious right in the US, a phenomenon often regarded with distaste in this country. But that is not the reason why we should be concerned about its attempts to influence votes in the House of Commons.

Let us be clear that The Independent on Sunday supports the Bill. On the most contentious question, that of so-called hybrid embryos, we believe that the potential gains to humanity in treating Alzheimer's, Parkinson's, motor neurone disease and similar conditions outweigh the objections. Glibly, such objections can be called the yuk factor, an involuntary recoiling from the idea of producing an embryo that is part human and part cow or rabbit, even if the cells are grown for only a few days to produce stem cells. This aversion is given more elevated expression by religious ideas about the point at which life – or a soul – comes into being. We do not accept, however, that the religious beliefs of a minority should be allowed a veto on medical research that benefits society as a whole. The question of whether the belief that life begins at conception should be recognised in law was settled in this country a long time ago. To those who believe it, the existing law on abortion should be far more offensive than a new law allowing the creation of embryo cells for a maximum of 14 days.

That, then, is the debate. Any individual or association of individuals has a right to put their arguments to MPs, who will vote on the Bill some time after next week's recess. But there are two grounds for concern about the way Care has sought to persuade MPs to vote against parts of the Bill. One is the use of paid interns apparently to obtain access and influence in the Palace of Westminster. The other is the question of what political activities are compatible with charitable status – a status that confers tax benefits on the organisation concerned.

The first is a complex issue, consisting almost entirely of grey areas. Trade unions fund researchers for many Labour MPs, and many companies pay for those of Conservative MPs. This is permissible under the Nolan rules dating from John Major's time, provided that the payments are not for the purposes of advocacy and, of course, that they are declared. It may be that these rules need to be reviewed, but Care seems to have crossed a line with its placing of research assistants in such intimate proximity to legislative power. It feels less like lobbying and more like infiltration.

The second issue appears to be more clear cut. Charities are quite rightly permitted to engage in political activity, including lobbying for or against changes in the law that affect their charitable purposes. But they cannot give their support to particular parties, politicians or candidates. These are important rules that should apply equally to charities that are thought of as left-wing and right-wing. In the past it was mainly left-inclined charities such as War on Want that chafed against such restrictions. Today, the pendulum has swung. But it remains important that both Care and, say, the Smith Institute, which has been accused of using its charitable status to promote Gordon Brown, should be subject to the same restrictions.

It is not because this newspaper supports the Embryology Bill that we take issue with the methods Care deploys in opposing it. It is because it appears to be using its money to purchase access to the House of Commons – access that is particularly valuable in seeking to persuade MPs in a free vote, when the usual disciplines of the whips' offices are relaxed. This gives this highly motivated campaign disproportionate leverage in the cockpit of democracy. As a first step, it should go without saying that all MPs should ensure that they have declared any support they have received from Care fully.

But it would be healthier for democracy and for the charitable sector if Care would back off and confine itself to lobbying MPs, like everyone else, at arm's length.