The Independent Group, set up by MPs who defected from Labour and the Conservatives, has applied to register as a political party in order to be able to fight European elections if they take place this year.
The group will stand under the party label Change UK - The Independent Group, if polls are held on May 23.
Former Conservative Heidi Allen has been selected as interim leader of the new party - and said while it was "hugely daunting", the "volume of support" from people suggested there was an appetite for a change to the existing political model.
The UK would have to stage elections to the European Parliament as a condition of any further delay to Brexit - and Ms Allen confirmed Change UK would field candidates if that election does take place.
Defeat for Prime Minister Theresa May in a vote on her Withdrawal Agreement in the House of Commons on Friday would greatly increase the likelihood of an application on April 12 for a long extension to the Brexit process.
In order to stand candidates in the European polls, conducted on a regional proportional representation system, any group must be registered as a political party with the European Commission.
Ms Allen said: "Today marks a huge step forward on The Independent Group’s journey to becoming a fully-fledged political party, so I am delighted to have been chosen as our interim leader.
"If we are to deliver on our ambition to change politics for the better, it is vital that we attract support from people from every walk of life, every political background and none.
"Coming into the House of Commons from running my manufacturing business in 2015, I have seen with my own eyes how improved our political system would be if it harnessed the diverse skills and experience of our country.
"We in Change UK, as we hope to be known, don’t just dream about a fairer and better future for our country, we are determined to unleash it through hard work, passion and shared endeavour."
TIG spokesman Chuka Umunna said Change UK would aim to put forward a "substantial" number of MEP candidates with backgrounds from outside politics.
"There is clearly an appetite for an alternative to our broken politics which needs fundamental change, as shown by the disastrous Brexit process which has occurred under the watch of the two main parties," said Mr Umunna.
"A new party will shake up the two-party system and provide people with an alternative that can change our country for the better. This is what Change UK will be aiming to do at any European elections if our application for registration is accepted in time."
The Independent Group was founded by former Labour MPs Luciana Berger, Ann Coffey, Mike Gapes, Chris Leslie, Gavin Shuker, Angela Smith and Chuka Umunna on February 18.
They were later joined by Labour defector Joan Ryan and ex-Tories Anna Soubry, Heidi Allen and Sarah Wollaston.
Close of nominations for any European elections will fall on April 24.