A spokesperson for Welsh Government has told ITV News that making the MMR vaccination compulsory was considered when Edwina Hart was Health Minister.
Such a move was ruled out "as it would adversely affect trust in doctors", said the spokesperson.
2013 is expected to be the worst year for measles in the UK for the past two decades. Read more about the illness and how it is treated.
If the Government's top adviser on immunisation thinks the risk of an emergency in England is a possibility, I believe him.