Religious Jews fear missing out on a 14 October election
Tens of thousands of religiously observant Jews will be unable to go to a polling station to vote on 14 October if a general election is called for that day, critics have warned.
The date slated for a proposed election clashes with the first day of Succot, a Jewish religious festival.
Observant Jews cannot vote on this day because activities associated with work - including writing - are prohibited on major festivals.
Number 10 has not yet commented.
David Landy, a religiously observant Jew who lives in Hendon, north-west London, will not vote in person if an election is held on that day.
He says: "I am astounded that someone at No 10 has not got access to a Jewish calendar."
Mr Landy, a married chartered surveyor with three children, adds: "It is more than a little inconvenient [to hold an election on 14 October].
"If I am not able to register for a postal vote in time, I would feel very disenfranchised."
Amanda Bowman, vice-president of the Board of Deputies of British Jews, said the organisation had contacted the government to explain the "concerns and difficulties" the community would face if an election was held on 14 October.
She added the Board of Deputies would be encouraging "everyone affected to apply for a postal vote so that their democratic rights are not affected".
People who will not be able to vote on the chosen day can register to vote by post or via a proxy vote.
Applications to vote by post must be received by 17:00 BST on 26 September, for those not already registered to vote.
Proxy voting - where another registered voter votes on another's behalf - must be applied for at least six working days before election day, in England, Scotland or Wales.
However, religious observance as a reason for a proxy vote is not covered in current published government guidance.
The same applications and deadlines for postal and proxy voting do not apply for Northern Ireland.
Prime Minister Boris Johnson said on Monday that he did not want an election.
But No 10 officials warned the prime minister would push for an election on 14 October if the government loses a bill to stop a no-deal Brexit.
Although there are no exact figures, there are roughly between 50,000 and 100,000 religiously observant Jews in the UK who could be affected by the possible election decision.
There are between 260,000 and 300,000 Jews in England and Wales and Jews represent about 0.5% of the UK's population.
There are concerns that voter turnout in constituencies with high proportions of Jewish voters could be impacted by a 14 October election.
Succot, also known as the Feast of the Tabernacles, commemorates the 40 years the Jews spent in the desert after the exodus from Egypt and celebrates how God protected them under difficult desert conditions.
Many Jewish people celebrate the festival by building open-air huts in their gardens, where they might take some of their meals.
Rabbi Zvi Solomons, of the orthodox Jewish community of Berkshire (JCOB), says he intends to contact Alok Sharma, the Conservative MP for Reading West, with his concerns.
Rabbi Solomons says he would be "terribly worried" if an election were held on 14 October.
He adds: "I am going to advise all my community to register for a postal vote."
Ms Bowman says: "If a general election were to be held on Monday 14 October this would coincide with the festival of Succot.
"This means that, due to religious restrictions, observant Jews would not be able to vote in person or participate on the day.
"While we understand that the situation surrounding Brexit means that there is very little flexibility over dates, we have been in touch with the government to explain the concerns and difficulties that our community would face. "