Unite is to donate £1.5 million to the Labour Party's campaign funds, the union has announced.

The union's executive expressed concern that the Government could be re-elected on a "tide of big business cash", while Labour remains under-resourced.

A statement said: "The executive council heard reports from the general secretary and the political director concerning Labour's general election campaign, the development of Labour's policy proposals on a range of issues of importance to Unite members and all working people, and Unite's own plans to campaign for the political change the country needs.

"The union is determined that the present Government should not be allowed to float to re-election on a tide of big business cash, while Labour remains under-resourced.

"The council therefore agrees to make a donation of £1.5 million to the Labour Party's campaign funds and will consider further support in due course."

The donation is separate from Unite's affiliation fees to Labour, which are worth around £1.5 million a year.

Unite halved the number of members it affiliates to Labour last year to around half a million following a review of Labour's links with unions instigated by party leader Ed Miliband.

It was agreed that affiliation fees should only be made on behalf of those who consented to the payment.

The move led to a cut in affiliation fees by Unite and the GMB union.

Conservative Party vice-chairman Bob Neill said: "This huge donation from Unite doesn't come for free. We all know Len McCluskey and Unite buy Labour's policies, choose Labour's leader and pick Labour's candidates."