There was a nasty surprise for Labour in the Queen's speech

David Cameron has been accused of using the Tories’ first majority in 17 years to launch a “shamelessly partisan” attack on Labour funding that could deprive the party of millions of pounds in donations.

Under plans unveiled in yesterday’s Queen’s Speech the Government said it would legislate to force all trade union members actively to consent to their subscriptions being used for political purposes. The move, if passed, is widely expected to result in a sharp fall in union donations to Labour which over the last five years have contributed more than £50m to the party. This represents around half Labour’s income.

The plans could also affect the ability of unions to campaign more broadly on political issues and are one of the most contentious aspects of the Tories’ new legislative agenda.

Labour reacted with fury to the plans to restrict political donations which senior party members fear could severely hamper their efforts to rebuild following a disastrous election defeat. A party spokesman pointed out that the Government was doing nothing to tackle large political donations from business and accused Mr Cameron of trying to “rig” the system to favour the Tories.

Paul Kenny, general secretary of the GMB, added: “It’s one rule for the Tory slush fund, hedge funds, and another for trade union members.

“It is not sustainable to allow the elite and companies unfettered and unlimited rights to fund the Tory party while shackling the bodies that have funded the political opposition to them for more than a century.”

A Downing Street spokesman said: “At the moment you are supposed to be able to opt out but there is concern that isn’t being spelled out very clearly to new members. There should be a conscious decision of opting in.”

More: The Queen's speech in numbers