Millionaire financier Gina Miller, who took the British government to court to put the decision on whether or not the UK actually leaves the European Union (EU) back in the hands of politicians, is back in the headlines.

The 51-year-old’s court-based campaign to ensure the government could not activate Article 50 of the Lisbon Treaty, which begins the Brexit process, without the permission of MPs was a success – even though controversial, taxpayer-funded leaflets advocating a Remain vote distributed during the campaign promised voters “This is your decision. The government will implement what you decide.”

Nevertheless, the government has now successfully passed legislation on the matter through the elected House of Commons, despite the determined resistance of a few holdouts.

The only obstacle to Article 50 authorisation now is the House of Lords. As in the Commons, the balance of opinion in the Lords is strongly in favour of the EU – but, unlike the Commons, the Lords are not elected and are therefore more liable to defy the will of the electors.

To encourage them and others to do so, Miller has launched campaign2018.org, telling the Evening Standard that, “In the face of no opposition, whoever feels the need to be the voice of reason needs to speak up now.”

“Currently MPs are too weak to do that,” Miller says, “so we must do it for them. If it doesn’t work, then we will try again with the Great Repeal Bill or try and get emergency legislation.”

Specifically, Campaign2018 aims to further empower MPs to amend or extend the Brexit negotiations, with “the possibility of [continued] membership” retained.

Previously, Miller had consistently denied that her campaigning activities were aimed at reversing the referendum result.

The Campaign2018 petition has been signed by a broad range of figures from the media and political class, including former BBC director-general Greg Dyke, former deputy prime minister Nick Clegg, and Labour MP David Lammy, who famously called on his parliamentary colleagues to “Wake up” and vote down the public’s “advisory, non-binding” vote for Brexit in the House of Commons.

At the time of writing, Miller’s petition has fewer than 3,200 signatures.