The Evening Standard, edited by the former Conservative chancellor George Osborne, has urged readers to consider voting Liberal Democrat in the European elections, in the latest sign of David Cameron-era Tories breaking with the party over Brexit.

The London newspaper said the Lib Dems had the “courage from the start to say the referendum result was a mistake” and as a result, “voters have started to think again about them”.

However, the Standard stopped short of a full endorsement for Vince Cable’s party, simply saying “we wish them well”.

Other prominent Conservatives have been punished by the party in recent days for endorsing the Lib Dems in the elections, including the former deputy prime minister Michael Heseltine. It is not known whether Osborne remains a paid-up member of the Conservative party, but the carefully phrased endorsement means he is likely to escape being censured.

Unsurprisingly, Osborne’s editorial attacked Jeremy Corbyn as an “extremist” who had indulged in “political cowardice” over Brexit, while suggesting there was also a case for voting Conservative in order to reduce the size of the Brexit party’s expected victory and “create the space for a leadership contender who makes the case for a radical return to the centre ground”.

Osborne, who was sacked by Theresa May shortly after she became prime minister, used the editorial to say she should have stepped down after the 2017 general election. “Instead, to the accolades of the worst manifesto, worst conference speech and worst parliamentary defeat in history, she is likely to add tomorrow the worst Conservative performance in a national election,” it said.

The Lib Dems are polling in second place behind the Brexit party ahead of the elections on Thursday, with some voters who abandoned the party during the coalition years seemingly willing to give it another chance thanks to an unambigious anti-Brexit message.

Osborne remains friendly with many of his erstwhile coalition colleagues. Last week, the former Lib Dem chief Treasury secretary Danny Alexander, now working with the Asian Infrastructure Investment Bank, posted a picture of him in California meeting Osborne and the former Lib Dem deputy prime minister Nick Clegg, who is now Facebook’s lobbying chief.

Danny Alexander (@dannyalexander) ...and delighted to have the chance to see some old friends too @George_Osborne @nick_clegg pic.twitter.com/oI3I0VBgs3

Osborne has edited the free London newspaper, which distributes 800,000 copies a day across the capital, since 2017. As with many papers, the Standard’s finances have been harmed by the decline in print advertising.

He recently announced a round of job cuts as part of a process to combine print and digital operations, and last month, Lebedev Holdings, the parent company owned by the Russian oligarch Evgeny Lebedev and a mysterious Saudi investor, pumped £5m into the newspaper through a new share issue.

The former chancellor would not be the first member of his family to back the Lib Dems. Osborne’s teenage son campaigned for Cable in Twickenham during the 2017 general election.