Moderate Conservatives have been warned to get ready to “battle” for control of the Tory party, as MPs position themselves to replace Theresa May as leader.

Nicky Morgan, the former education secretary, told HuffPost UK that “now is the time for liberal Conservative voters to sign up and become members” of the party.

Her call came as Leave.EU, the campaign group founded by former Ukip donor Arron Banks, urged hard Brexiteers to join the Tories to “take back control of the party”.

The group has branded May’s Chequers Brexit plan “a complete sell out” and pro-Remain Tory MPs “faux-conservative traitors”.

Boris Johnson is currently the grassroots favourite to takeover as Tory leader after he quit the government in protest at May’s plan being too soft.

Philip Lee, the pro-Remain former minister who quit the government because he felt the PM’s plan was too hard, has warned about “entryism” into the party by the “hard right”. 

In an attempt to fight back against hard Brexiteers, Morgan said “any group attempting to flood the party membership does a disservice to the history we have as a party of being a broad church”.

“There will be a battle for the future direction of the party and now is the time for moderate Conservatives to step up and champion their values to ensure that we can be the party of hope and aspiration,” she said.

She added: “We have witnessed in the Labour Party what happens when the moderates don’t speak up.”

Morgan is a patron of the liberal Tory Reform Group. Owen Meredith, the chairman of the organisation, warned the party would become “unelectable if dragged off the extremes”.

“The strength of the Conservative Party has always been in its broad church. It is vital that people who share conservative values join the party and strengthen our movement, wherever they sit in that church,” he said.

“The easiest way to ensure we are anchored in the centre ground is if the membership reflects the centre-right coalition of voters in the country who support us.”