Mr. Peter Thompson:

There is the general population. How screening works is explained properly to everybody. We are just talking about screening for chromosomal abnormalities. At this point, between 30% and 40% will say they are not interested and opt out immediately.

The second step, so to speak, is that a risk is ascertained. When people are informed of the risk and despite the first risk, some people will actually say they had the test because they just wanted it to be low in order to have some good news and reassure them. Other people will view the risk they get as actually not very high anyway. We have a cut-off risk of one in 150 at which we will offer invasive prenatal diagnosis. Some people might view one in 140, for example, as a low risk and then not go on to have invasive prenatal diagnosis.

Those women who go on to have invasive prenatal diagnosis, which carries a risk of miscarriage meaning that for the first time they are doing something that carries a risk of miscarriage, are doing it for three main reasons: it would impact on how the baby would be managed after birth; some people feel that once they have been given this higher risk, they just have to know; and other people do so because they are going to act on the result. A high proportion of people in the end, therefore, act on the result because they have been through several screening processes beforehand whereas people who would not act on that result actually cannot get that far. I am not sure if I explained that properly to the Deputy.