It is Brexit (7) - Role of Parliament in Brexit decision and notification to EU

The question of what role Parliament should play in relation to the United Kingdom making a "decision" to withdraw from the EU was discussed in an earlier post - It is Brexit (3) - where I both advanced the view that an Act of Parliament was required and also included a list of links to arguments for and against that proposition.  It has been announced that legal steps are being taken to try to secure the involvement of Parliament - see Mishcon de Reya - Article 50 process on Brexit faces legal challange to ensure parliamentary approval.   The Mishcon de Reya statement informs us that the action is being taken 'on behalf of a group of clients' but they are not named.