An important test of nerve on the path to Brexit (or perhaps not) may arise today.  

A cross-party group of MPs (including prominent figures such as Nicky Morgan and Yvette Cooper) has tabled an amendment to the Finance Bill which, if it is called by the Speaker, could prove a significant barometer of MPs' resolve to prevent a no-deal Brexit.

The proposed change relates to a rather boring administrative provision towards the end of the current draft of the Finance Bill which, amongst other things, allows the Treasury to make regulations to maintain the effect of UK tax legislation or to fix deficiencies in UK tax legislation at the time of Brexit.  

If enacted, the amendment would only allow the powers to be used if Parliament has approved a negotiated withdrawal agreement with the EU, the Government has sought an extension of the Article 50 period, or Parliament has expressly approved leaving the EU without a withdrawal agreement. 

The immediate effect would be to prevent the Treasury making use of the provision in the event of a ‘no deal’ outcome without the consent of Parliament.  The intention is clearly to prevent the slide towards a no deal outcome without the involvement of Parliament - which is otherwise the default option under both the Article 50 process and existing UK legislation.