Security has been tightened in Jewish neighbourhoods ahead of the High Holy Days.

The Community Security Trust said “a robust policing plan” would be in place to protect the community during the festivals, with police and CST volunteers mounting patrols.

CST said it had held briefings with shuls and police across London and Manchester.

A spokesperson stressed that there was no indication that the level of threat was higher than normal.

Police had raised the alert level after the attack on a kosher supermarket in Paris in January, in which four people were killed.

The spokesman said: “That risk still stands and while there is no credible threat, there is a heightened sense of fear within the community.”

He added: “Because there are more visibly Jewish people around during the holiday period there is an element of extra risk and security operations are in place to cover that.”

There was “a strong security blanket across the community,” he said.

Detective Superintendent David Palmer, who is leading the policing activity for the Metropolitan Police during the festivals, said: "The High Holy Days are when Jewish communities are perhaps more visible, as larger numbers go to worship during this time. We will therefore continue to work with the Jewish community, as we do with all communities, to reduce the threat to them during this period.

"We are centrally co-ordinating our policing activity for the High Holy Days through the Met's Counter Terrorism Protective Security Command."

He added that officers from some London boroughs will be carrying out patrols accompanied by representatives from local Jewish community groups.

He urged the public to remain vigilant and inform police of any suspicious or unusual activity.

The threat level from international terrorism in the UK remains at severe, DS Palmer said, "so we all have a role to play in preventing any attacks".

Suspicious activity can be reported to the police by using the anti-terrorist Hotline on 0800 789 321.

In Stamford Hill, north London, the Independent Advisory Group has organised extra security for the Charedi community.

IAG chair Moishe Friedlander said: “While there is no specific risk I have been liaising with the police to make sure the patrols of the shuls during the holidays are done as standard.”

Inspector Jeoff Bull, of Hackney Police, said: “We have worked closely with the IAG to provide additional bespoke resources for the High Holy Days, tailoring our plans to support places of worship and residential areas.

“In 2015 there is no intelligence to suggest any direct threat to our communities but we all must exercise vigilance in times of world political anxiety.”

He added that police “looked forward” to the High Holy Days as they were a chance to meet many in the community and get to know them.