London (AFP) - A Jewish group has criticised Britain's response to the migrant crisis, recalling that Jews were once the focus of an immigration scare in a letter to Prime Minister David Cameron Wednesday.

"Many of us in the Jewish community are appalled by the UK's response to the ongoing situation in Calais," read the open letter from the Jewish Council for Racial Equality, which assists refugees and asylum seekers.

"Our experience as refugees is not so distant that we've forgotten what it's like to be demonised for seeking safety."

Immigration is one of the most sensitive issues in British politics, and images of migrants trying to illegally cross the Channel to Britain from the French port of Calais have been splashed across newspapers in recent weeks.

The letter referred to Cameron's much-criticised description of the migrants as a "swarm", and noted that Britain received fewer requests for asylum compared to other countries in Europe.

"People fleeing conflict and persecution are not to blame for the crisis in Calais," the letter read.

"We in the UK are not the victims here; we are not being invaded by a 'swarm'."

The group called on Cameron to work with other European countries to offer "safe and legal routes" to asylum seekers.

"We are facing the largest refugee crisis in a generation," it read. "Our response must be better than putting up fences around our borders."

The numbers of migrants fleeing war and poverty in the Middle East and Africa to Europe has jumped in recent months and years as instability has gripped Syria, Iraq and North Africa.

The British government has responded to the repeated attempts by migrants to reach England with sniffer dogs and more fences, and last week, it announced a crackdown on illegal immigrants inside Britain.

Jewish refugees from Nazi Germany were not universally welcomed in Britain and in the 1930s newspapers warned against admitting too many in the same language used about refugees from the Middle East and Africa today.

Cameron's office did not immediately respond to a request for comment.