Is Brexit a deadman walking?

The dramatic shift last weekend in Labour’s position on Brexit – to one where it backs membership of the single market and customs union during a transition period after Brexit, and possibly for good – puts May in far greater danger than before. It raises the real prospect that a pro-single market amendment tabled by a Tory rebel could attract enough Labour, SNP, Lib Dem and other support to bring about a government defeat. Anti-hard Brexit Tory rebels will not back a Labour amendment, but Labour could very well back one from a Tory, if it is in line with its new policy.