Prime Minister Theresa May has told a Jewish audience attending a Rosh Hashanah reception at 10 Downing Street that she is a “proud supporter of Israel” ahead of the centenary of the Balfour Declaration.

She said: “Born of that letter, the pen of Balfour, and of the efforts of so many people, is a remarkable country….As Prime Minister, I am proud to say that I support Israel. And it is absolutely right that we should mark the vital role that Britain played a century ago in helping to create a homeland for the Jewish people.”

May used the annual address to reassure the community on security funding and counter-extremism efforts, saying that she was hoping to establish the Commission for Countering Extremism as a statutory body, with extra power to tackle hatred.

She also said she would “actively encourage” use of the newly-adopted working definition of anti-Semitism put forward by the International Holocaust Remembrance Alliance by the “police, legal profession, universities and other public bodies”.

The IHRA definition has caused controversy since it expands the remit of actions and comments that can be considered anti-Semitic to include criticism of Israel.

The Tory leader also acknowledged the work of volunteers such as Marsha Gladstone, the mother of Yoni Jesner who set up a foundation encouraging youngsters to volunteer in his name.

Gladstone, a Scot living in Glasgow who was named Volunteer of the Year by the Jewish Volunteering Network, is soon to move down to London, where most of the foundation’s core work is based.