Ukrainian resistance to the Russian invasion is “heroic” but the country should not abandon civil liberties in wartime, a Brexiteer and champion of religious freedom has urged. There is strong concern about the future of the Ukrainian Orthodox Church, which campaigners fear could be banned despite its insistence it has cut links with the Moscow Patriarchate.

Lord Jackson of Peterborough, a leading member of Parliament’s all-party group on freedom of religion or belief, said: “President Zelensky and his people are rightly viewed as heroes for their skilful and brave resistance to unprovoked Russian aggression. But they should not lose track of what they are fighting for – freedom, democracy and the rule of law.”

Lord Jackson said it “would be a tragedy if these principles are lost in the fog of war with Putin,” warning: “Shutting down the country’s oldest church will only sow the seeds of future social unrest.”

There are two main Orthodox churches in Ukraine – the Orthodox Church of Ukraine and the Ukrainian Orthodox Church. Last year Ukraine’s Parliament passed a bill which it is feared will result in a de facto ban of the latter church.

In August the late Pope Francis stated: “Please, let no Christian Church be abolished directly or indirectly.”

There are concerns that if the Government concludes the church’s headquarters is linked to Moscow then mass closure of monasteries and churches could follow.

Lord Jackson said: “While it is legitimate to arrest and charge individuals within a religious organisation for crimes of treason or collaboration, to ban an entire church for the crimes of a few is a gross abuse of power.”

It is a “moral imperative” for Britain to provide military and humanitarian aid to Ukraine, he said, and he described the UK’s role as a “source of pride”.

But he added: “It is important for Ukraine to carefully consider its religious policy to ensure they align with its long-term goal of integration into the Western world. Yes, Ukraine must defend itself from the malign influence of Russia, but this must not come at the cost of civil liberties that protect some of the most marginalised groups in society.”

The UK Government says Ukraine is well known for its commitment to pluralism, including freedom of religion and belief. It has been assured the controversial law has been developed in response to the “clear national security threat” posed by Russia – but it says it will track how it is used closely.

The UK insists the only way for freedom of religion and belief to be fully assured in Ukraine is for Russia to cease its attacks, end its invasion and withdraw its troops.

According to the United States Commission on International Religious Freedom, Russia has “committed gross religious freedom violations in Ukraine”. Russian forces have “frequently damaged and destroyed religious buildings and other sites and killed or injured those sheltering or worshiping in these places” and religious leaders have been “abducted and tortured”.