Abortion is the induced termination of a pregnancy to destroy the foetus. In the UK, abortion is legal up to the 24th week of the pregnancy. After that time an abortion can be carried out if there is a serious threat to the life of the mother or the foetus is severely disabled. According to the current law, at present a woman must have the agreement of two doctors for the termination. The 24-week rule was introduced in 1991, as it was established then that babies born at 24 weeks are viable and with intensive care can survive. The principle behind this ruling is that, whatever the reasons for an abortion, a foetus should be given legal protection if it is possible for it to survive outside the womb. Medical science has now moved on, and there is some pressure to lower the time to 20 weeks, but as yet this has not happened.