Theresa May is siding with aides who argue that supporting a customs union with the EU would destroy the Tory party

Theresa May’s government is facing meltdown today as The Sunday Times reveals how a senior House of Commons official helped rebel MPs who are plotting to derail Brexit.

Leaked emails obtained by this newspaper show that Dominic Grieve, the former attorney-general, has been in secret communications with Colin Lee, the clerk of bills, with the explicit intention of suspending Britain’s departure from the European Union.

Lee drew up three versions of the plan for Grieve — each of which would overturn centuries of parliamentary precedent — and then swore him to secrecy.

MPs will tomorrow unveil their plan to hijack the agenda of the Commons to suspend article 50, the mechanism by which the UK is leaving the EU.

The revelations came as the