Charities that campaign extensively for their causes during the forthcoming election might have to register with the Electoral Commission, even if they comply with all the latest Charity Commission guidance.
The warning comes in a revised version of the commission document Charities and Elections, released today. It says registration may be necessary if charities "use material that could be seen as indicating to the public that particular candidates or parties support or oppose their policies".
Any organisation that campaigns publicly for or against any political issue in an election period and spends more than £10,000 in England or £5,000 in the rest of the UK is required to register with the Electoral Commission. Its spending limit is then raised to £793,000 in England.
The Charity Commission's guidance emphasises that charities must not support or oppose political parties or candidates, or donate to them. A charity can campaign on a policy that coincides with that of a political party, it says, providing it makes clear its independence from that party.
The guidance also confirms that it is legitimate for charities organising hustings not to invite candidates who advocate policies that contravene their objects, or whose views are likely to alienate its supporters.
The electoral guidance is the first since the commission revised its CC9 campaigning guidance in 2008. There have recently been several investigations into charities that have strayed into political territory, including Catz Club, which made two donations to the Labour Party in 2008.
Rosie Chapman, director of policy and effectiveness at the commission, said that the document was not a "finger-wagging" response to such cases. "Charities' campaigning role is valued by the public, but the price to pay is that you need to make sure you are squeaky clean if you are to maintain public trust," she said.
Brian Lamb, executive director of advocacy and policy at the RNID, said there would be more scrutiny of campaigning charities this year than during previous elections. This was because the sector had higher political prominence than ever before, the opinion polls were closer and social policy was likely to be a key battleground, he said: "That will suck the sector into wanting to campaign."