The Independent Group for Change, the party established by centrist MPs defecting from the two main parties, is being closed down, with its leader saying it was “better to have fought and lost than never to have fought at all”.

The party, started by disillusioned Labour MPs in February, unsuccessfully stood three candidates in the general election, with all losing out to their previous parties.

In a letter to members on Thursday, the party’s leader, the former Tory MP Anna Soubry, said the group had been formed “in response to the broken state of British politics”. She said they had hoped “more Labour and Conservative MPs would share our courage and leave their respective political parties”.

“Whilst there is clearly a need for massive change in British politics, now that we no longer have voices within parliament, a longer-term realignment will have to take place in a different way,” said Soubry. “Honesty and realism are at the core of our values, and we therefore must recognise that the political uncertainty of recent months has now given way to a settled pattern in parliament for the next five years. So this is the right time for us to take stock.”

She added: “We have no regrets about standing up and speaking truth to power when the country needed it. It was always better to have fought and lost than never to have fought at all.”

The party was founded when seven Labour MPs, including Chuka Umunna and Luciana Berger, announced they would be leaving the party over its Brexit position and handling of antisemitism. They were then joined by three Conservative MPs.

Despite recruiting high-profile candidates for the European elections in May – including Boris Johnson’s sister, Rachel Johnson – Change UK, as it was then called, polled just 3% and failed to return any MEPs. Five of its MPs, including Umunna and Berger, quit the party to join the Liberal Democrats.

Soubry said on Thursday that the party’s management council had unanimously agreed to wind up the organisation, ending members’ monthly subscriptions and beginning the process of closing down its office. She said it would contact the Electoral Commission to deregister as a political party.