The rival groups bidding to lead the Brexit campaign in the EU membership referendum will go head to head on Friday.

Each is submitting its formal application to the Electoral Commission which will select the lead campaigns for Leave and Remain. The chosen teams will be allowed to spend millions on campaign broadcasts and mail shots.

While only one group, Britain Stronger In Europe, is expected to lead the argument for the UK’s continued membership, the Leave designation is being bitterly contested.

Vote Leave was initially considered the front-runner. It is being backed by senior ministers including Michael Gove and Chris Grayling, as well as Iain Duncan Smith who has just resigned from the Cabinet and the London Mayor, Boris Johnson.

But it is being strongly challenged by the Grassroots Out group, which stresses its popular credentials. It has the backing of Conservative and Labour MPs, as well as the Ukip leader Nigel Farage.

The rival groups held a secret meeting on Monday chaired by Mr Grayling to discuss their differences, but they are both still putting their names forward.

The Electoral Commission is due to make its decision in about ten days’ time.