Think-tanks with close links to political parties are facing a crackdown by the Electoral Commission to ensure that they comply with strict rules on campaign spending.

The elections watchdog believes that campaigning organisations, including think-tanks and trade unions, can be unaware that their activities amount to campaigning on behalf of a party, which must be declared to the commission before an election. This includes material intended to “procure electoral success or disparage a party or group”, whether or not the material expressly mentions the names of the party or candidate.

The watchdog is already monitoring the campaigning activities of such groups before next week’s local elections, and will then compare it with what the organisations declare.

The Smith Institute, with links to Gordon Brown, and Policy Exchange, which is close to David Cameron, have come under fire for their activities, which opponents say are partisan. The Charity Commission is currently examining the work of the Smith Institute over whether it is politically independent and could retain its charitable status.

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