London, UK - Attacks on Jews in the UK reached record levels in 2009, according to figures compiled within the community.
The Community Security Trust (CST) said it had recorded 924 incidents over the year, 55% more than the previous high of 598 incidents in 2006.
The organisation, which monitors incidents against Jewish people and organisations, said the rise was linked to last year's Gaza conflict.
Prime Minister Gordon Brown described the figures as "deeply troubling".
The CST is a Jewish community organisation which collects figures on attacks and advises organisations such as synagogues on security.
It works closely with the police and government on combating racial and religious hatred.
The organisation says the record rise follows two years of falling figures, with the majority of the incidents occurring during or immediately after the conflict in Gaza between Israel and Hamas.
The two-month Gaza conflict began in December 2008 and the CST said acts of anti-Semitism shot up in January and eventually levelled in April.
The vast majority of incidents were abusive behaviour, but 124 of the reports were acts of violence. Some 37 incidents were targeted at children on their way to school, the organisation said.
In a statement issued through the CST, Gordon Brown said: "The increase in anti-Semitic incidents recorded by CST in the early part of last year is deeply troubling and I want to be unequivocal today.
"I am a proud friend of Israel and welcome a robust debate about how we ensure both a secure Israel and a viable Palestinian state existing side by side.
"The debate is welcome, but no strength of feeling can ever justify violent extremism or attacks and we will stand firm against all those who would use anti-Israeli feeling as an excuse or disguise for anti-Semitism and attacks on the Jewish community."
One incident included strips of bacon being placed on the door handles of a Leeds synagogue. On another occasion, a 12-year-old girl, the only Jew at her school, was surrounded by other pupils who chanted "death to Jews".
Shadow schools secretary Michael Gove said: "Every one in public life - politicians, media figures, academics and community leaders - has to recognise that this growth in anti-Semitism is a stain on our society.
"History tells us that whenever Jewish individuals feel less safe, society as a whole is becoming less free. We must learn the lessons of the past."
And the Liberal Democrat's home affairs spokesman Chris Huhne said: "We must do everything we can to prevent foreign conflicts from spilling over on to British streets and campuses."
The police and government agencies do not use the CST's figures and instead rely on statistics for recorded offences and convictions in courts.
The most up-to-date figures on hate crimes suggest there was a fall in racial and religiously aggravated incidents between 2007 and 2008.
Some police forces calculate local trends for religiously motivated incidents, but there are no national figures for hate crimes against any specific group, such as Jews or Muslims.
Last month, researchers at Exeter University called on Muslims to start counting their own figures in a similar fashion to the CST, saying there was evidence of an under-reporting of anti-Muslim hatred.