The Criminal Justice Act 2003 modified the ancient legal principle of double jeopardy in England and Wales so that a person acquitted of a serious crime could be re-tried. Now in Scotland there is a clamour to change the law too, and the government is committed to introducing legislation in 2010.

But there are voices of dissent, as Simon Cox finds out. And if the law is changed, will it enable the reopening of the case that is driving the Scottish debate? Helen Scott and Christine Eadie were murdered in 1977 after they were seen leaving the World's End pub in Edinburgh. Angus Sinclair was tried for the killings in 2007, but the case collapsed due to insufficient evidence.

In England and Wales, meanwhile, only a handful of double jeopardy cases have returned to court. Is the law working as it should? Show less