Charities planning to take part in next month’s pro-Palestinian rally in London, marking the 40th anniversary of the Six-Day War, have been warned to abide by regulations set out by the Charity Commission.

At least nine major charities are expected to take part in the demonstration on June 9, which the organisers claim will attract tens of thousands of participants. They include Friends of the Earth, War on Want, Medical Aid for Palestinians and Interpal.

A spokesman for the commission said it had received messages of concern that by supporting the Enough Coalition rally, the groups may be breaking the rules preventing charities from becoming political bodies.

"We contacted all the charities involved, reminding them of the factors they should consider when becoming involved with this sort of initiative," said a spokesman.

The watchdog had reminded them of its guidance on campaigning and political activities.

According to the Commission’s regulations, charities are allowed to take part in demonstrations or political campaigning designed to further their philanthropic aims.

But it adds: "An organisation set up for a purpose… of advocating or opposing a change in the law or public policy in this country or abroad, or supporting a political party, cannot be a charity."

A Board of Deputies spokesman urged the commission to monitor charities "engaging in overt political activity", and called for a robust response to those that "deliberately push the bounds of what is permissible to, or beyond, acceptable limits".

One of the charities taking part in the rally, War on Want, is being monitored by the commission following complaints about two leaflets it has distributed.

One accused companies of "profiting from the occupation" of Palestinian areas, and another said: "Together we can break down Israel’s apartheid wall".

Although there was no formal investigation of the charity’s activities, the commission maintained an "open case" on the matter. A spokesman told the JC that the Charities Commission "had been in correspondence with the charity and is currently awaiting a response on the issues that have been raised."

See also: ‘Charity under fire’ , Bernard Josephs, The JC, May 11, 2007