Labour’s ruling body has approved a new code of conduct on anti-Semitism despite intense criticism from the party’s MPs and peers as well as Jewish leaders.

The document states explicitly that “anti-Semitism is racism” and it is “unacceptable”, but stops short of signing up in full to the definition drawn up by the International Holocaust Remembrance Alliance’s (IHRA).

At a meeting of the Parliamentary Labour Party on Monday, MPs and peers overwhelmingly backed calls for the full wording to be adopted.

Chief Rabbi Ephraim Mirvis warned that adopting the code would “send an unprecedented message of contempt to the Jewish community”.

But Labour’s National Executive Committee signed off the code at a meeting on Tuesday.

Members agreed, however, to re-open the development of the policy in recognition of the “serious concerns” raised.

Labour former leader Ed Miliband said the party should adopt the full definition.

He said: “The argument that it is somehow incompatible with criticising the actions of the Israeli government is wrong.

“The views of the vast majority of the Jewish community are very clear. I would urge the NEC to get on with this at speed.”

Labour MP Ian Austin said the move was “utterly shameful”.

He added: “I am ashamed to be a member of the Labour Party.”

Labour officials drew up the code in the wake of protests by Jewish groups outside Parliament earlier this year.

It states that criticism of the state of Israel and its policies should not automatically be regarded as anti-Semitic, and makes clear that even “contentious” comments on this issue “will not be treated as anti-Semitism unless accompanied by specific anti-Semitic content … or by other evidence of anti-Semitic intent”.

The code explicitly endorses the IHRA’s working definition of anti-Semitism and includes a list of behaviours likely to be regarded as anti-Semitic copied word-for-word from the international organisation’s own document.

But it omits four examples from the IHRA list:

– Accusing Jewish people of being more loyal to Israel than their home country;

– Claiming that Israel’s existence as a state is a racist endeavour;

– Requiring higher standards of behaviour from Israel than other nations; and

– Comparing contemporary Israeli policies to those of the Nazis.

Labour insisted that while the examples are not reproduced word for word, they are covered in the new code.

In a statement, the Jewish Labour Movement said: “The Labour Party has acted in a deliberate and offensive reckless manner in believing it understands the needs of a minority community better than the community itself.”

Labour Against Antisemitism said it was looking at its legal options and would be making a formal complaint to the party.

Spokesman Euan Philipps said: “The message sent by the NEC is loud and clear: the Labour movement has lost its moral compass, appears to have an institutional anti-Semitism issue and can no longer claim to represent the values of solidarity, justice and equality.

“It is now up to those Labour MPs who supported the IHRA definition at Monday’s PLP meeting to examine their consciences and decide whether they can continue to support this Labour leadership.”

Gideon Falter, chairman of Campaign Against Antisemitism, said: “It is for the Jewish community to define anti-Semitism.

“We have been consistent and clear in demanding that the Labour Party follow the Government, police, other political parties and even its own MPs in adopting the international definition of anti-Semitism.

“Today the NEC crossed the Rubicon and defiantly adopted its own deeply inadequate definition.

“We have long stated that the Labour Party under Jeremy Corbyn is institutionally anti-Semitic and unsafe for Jews.”

Jewish community groups condemned the NEC’s decision and warned “on its current trajectory, Labour is failing British Jews and it is failing as an anti-racist party”.

In a joint statement the Board of Deputies, Jewish Leadership Council and the Community Security Trust said: “The decision taken by the NEC today to adopt a watered-down definition of anti-Semitism will be regarded with a mixture of incredulity and outrage by the overwhelming majority of the UK’s Jews.”

The groups added: “The NEC has chosen to disregard the views of the Jewish community, an unprecedented show of unity by rabbis from every part of the community and even its own parliamentarians.

“They have distorted and diluted the IHRA definition of anti-Semitism that is widely accepted and used by the Jewish community, the UK Government, the Scottish Parliament, the Welsh Assembly, the Crown Prosecution Service, the police, and dozens of local authorities, to create their own weaker, flawed definition whose main purpose seems to be to protect those who are part of the problem.”

A Labour Party spokesman said: “The NEC upheld the adoption of the Code of Conduct on anti-Semitism, but in recognition of the serious concerns expressed, agreed to re-open the development of the code, in consultation with Jewish community organisations and groups, in order to better reflect their views.”