'Bishop in Europe' Dr Robert Innes has written to Prime Minister Boris Johnson with a warning that a no-deal Brexit will be "disastrous" for the UK.
In his letter, Dr Innes, who is Bishop of Gibraltar and chief pastor in the Anglican Diocese in Europe, said that the Prime Minister and Government must "do everything they can" to avoid leaving the EU without an agreement in place.
The Government should also take into consideration the impact on the many British people currently living in other parts of the EU, whom he said felt like "a forgotten million".
"Seen from my diocese, continental Europeans care very much about us in the UK, and for the future relationship we choose to define with the European Union," he wrote.
"The UK currently finds itself simultaneously in deadlock at home, and at an impasse with the rest of the EU.
"I take a close interest in the way in which over 3 million EU citizens are being treated and represented, particularly in the Brexit context: 2 million plus EU27 citizens resident in the UK, as well as the estimated 1.2 million UK nationals living in the EU27.
"It is no wonder many people in my Diocese believe they are seen as 'a forgotten million' by the UK Government.
"There are a huge range of issues that are concerning people, not least on citizens' rights issues around residency, healthcare, working, doing business, drawing pensions, travelling, and studying.
"A no deal scenario would be disastrous for the UK, and I urge the new UK Prime Minister and Government to do everything they can to avoid it."
It is the second time this week that the Prime Minister has been warned by the UK Church not to pursue a no-deal Brexit.
Church leaders have until now largely remained neutral on the particular details of a Brexit deal, commenting mostly on the tone of the debate and the need for the UK to maintain a good relationship with the EU going forward..
However, after Mr Johnson took office on Wednesday, the representatives of eight denominations said in an open letter that they felt "compelled" to challenge a no-deal Brexit because so little evidence had been put forward to support assurances that it would not be detrimental to the country.
They warned that a no-deal Brexit would be "irresponsible" and leave the poorest people even worse off.
"At a time when increasing numbers of families have difficulties putting enough food on the table, we believe it is irresponsible to consider a course of action that is expected to make that situation worse," the letter reads.
"It is notable that assurances about our ability to cope with a no-deal Brexit, while frequent, are yet to be supported by substantial evidence."
The letter was signed by leaders from the Baptist Union of Great Britain, The Salvation Army, Methodist Church, Quakers, United Reformed Church, Baptist Union of Wales, Church of Scotland, and Scottish Episcopal Church.
Mr Johnson has vowed to lead the UK out of the EU "no ifs or buts" by the October 31 deadline, and said in his first statement in the House of Commons since becoming Prime Minister that he is committed to "getting rid" of the Irish backstop.
"No country that values its independence, and indeed its self-respect, could agree to a treaty which signed away our economic independence and self-government as this backstop does," Mr Johnson said.
"[It] poses that appalling choice to the British government and the British people - to the United Kingdom - of losing control of our trade, losing control of our regulation or else surrendering the government of the United Kingdom."
