A group of British citizens is seeking to crowdfund a challenge to government plans to use royal prerogative powers to invoke article 50 of the Lisbon Treaty, the mechanism which formally begins the EU exit process.

Changes to the ‘citizenship’ of British citizens that would result from Brexit are central to the arguments put forward by the group. It is the second legal challenge known to be in preparation.

Grahame Pigney, a British citizen resident in France, leads the group, which has instructed Bindmans solicitor John Halford (pictured).

Pigney said: ‘The enforced removal of citizenship rights from 65 million people is completely unprecedented in a modern democracy. If it is to happen, it must involve a proper parliamentary process.’

Halford added: ‘Our legal arguments are focused on the undemocratic threat to ordinary citizens’ rights, not business interests. A range of ordinary citizens are bringing it to make sure the collective frustration, fears and concerns about that threat is clear to the court.’

During the referendum campaign Pigney ran the grassroots group Say Yes 2 Europe. Halford is a public law specialist whose high-profile cases include a successful challenge to the legality of the government’s proposed legal aid residency test.

The CrowdJustice fund has a target of £50,000. 

Mishcon de Reya is pursuing an entirely separate challenge on behalf of a group of clients. Its position is that an act of parliament is required for article 50 to be invoked legally.