The right of midwives to refuse to participate in abortions on the basis of their religious beliefs is explicitly protected by the 1967 Abortion Act, and has historically been respected by the hospital.
However, the hospital recently changed its stance by imposing an obligation on midwives to watch over, and sometimes assist, with late abortions, which were frequently being transferred from the gynaecology department to the labour ward.
Sources:
http://www.bbc.co.uk/news/uk-scotland-glasgow-west-16596605
http://www.christian.org.uk/news/midwives-claim-nhs-ignored-abortion-objections/