Over 20,000 people have signed a petition calling on the Lib Dems to reinstate David Campanale, who is suing the party over his deselection.
Campanale has launched legal action against the party claiming that he was deselected because of his Christian beliefs. The Lib Dems have denied the claim and said they are "home to people of all faiths and none, including many Christians".
A separate complaint lodged with the Equality and Human Rights Commission (EHRC) over the matter alleges that Campanale, a practising Anglican and former BBC journalist, was "mocked and abused" over his faith.
He has been replaced as the candidate for Sutton and Cheam by Luke Taylor. An appeal of his deselection is ongoing.
It is believed to be the first time that a political party has been sued for discrimination because of someone's Christian faith.
The petition, on CitizenGo, calls on Ann Glaze, Chair of London Liberal Democrats, to reinstate Campanale as the candidate for Sutton and Cheam.
It claims that Campanale has faced "undue hostility" for his Christian faith and says that not reinstating him will be "damaging" to the party.
"It suggests Christians are unwelcome in the party," reads the petition, which has been signed by 23,000 people so far.
Critics have drawn parallels with the fate of Tim Farron who resigned as party leader in 2017 after facing intense media scrutiny over his Christian faith. At the time he said that "remaining faithful to Christ" was incompatible with being party leader.
The Bishop of Guildford, the Rt Rev Andrew Watson, is among the signatories of the petition in support of Campanale. He said that conservative Christians can be subjected to "hostile and degrading questions" that other people of faith are not asked.
"We are quite rightly as a nation very aware of and critical of other parts of the world where people are discriminated against on the basis of their religion and faith," he told The Telegraph.
"It is important that we are not pointing the finger at others whilst doing the same thing ourselves. It is important that people of faith can participate in public life."
Other signatories include Lord Alton, a former Lib Dem MP and now crossbench peer, who said that party leader Ed Davey "needs to reverse a shocking decision".
"I have signed this petition against appalling treatment that is neither liberal nor democratic and hope others will do so too," he wrote on X.
The Bishop of Winchester, Philip Mounstephen, author of the government's 2019 review into persecution, responded to the tweet by saying, "I agree."
"The deselection of David Campanale on the grounds of his beliefs alone is shockingly illiberal. On this basis [19th century liberal prime minister] Gladstone wouldn't have been allowed to stand in Sutton and Cheam," he said.
