Stefan Wermuth / Reuters
Leave.EU co-founder Arron Banks said the Electoral Commission's decision to designate Vote Leave as the official Out campaign "doesn't make sense"
A key group of Brexit supporters is considering taking legal action against the Electoral Commission over its decision to choose a rival group - Vote Leave - as the official Out campaign.
Leave.EU, which claims on its website to be Britain's fastest growing grassroots movement, is due to confirm at noon on Thursday whether it will launch a legal challenge against the Commission's decision - a move that could potentially delay the referendum by up to sixth months.
The Electoral Commission - an independent body responsible for regulating election finance - announced Vote Leave as the official Out campaign on Wednesday. This means the cross-party group backed by London mayor Boris Johnson can spend up to £7 million of public funds.
Arron Banks, who co-founded Leave.EU, accused the Commission's judgments of being inconsistent with its criteria and said the group has been the victim of a "political stitch-up."
Banks, who in 2014 donated £1 million to Nigel Farage's UKIP, said: "There are a number of judgments according to the Electoral Commission's own criteria that do not make sense and we shall be raising those inconsistencies in our action."
He added: "It is to be regretted that this process may put the referendum back until October, but if we are to avoid the most important vote of our lives being rigged then I feel duty bound to take this course of action."
As well as having access to millions of pounds of public funds, Vote Leave is able to send mailshots to voters for free, and can put forward its argument for Britain to leave the 28-nation bloc in TV broadcasts.
Leave.EU has conducted internal discussions and said it will announce a decision on whether it will submit an application for judicial review by 12.00 p.m. (BST) on Thursday, according to The Guardian.
The Commission's decision also dealt a blow to Nigel Farage-backed group Grassroots Out, which was also vying to become the official Out campaign. However, the group congratulated Vote Leave over Twitter and said it was prepared to work together to win the June 23 referendum.