Eurosceptics should not wait for the result of David Cameron's "timid" renegotiation with the EU and must start campaigning for a Brexit, John Mills has urged. The Labour donor, writing exclusively for IBTimes UK, said the prime minister's talks with Brussels have been a "tragedy" and a "missed opportunity" for Britain and the 28-member-bloc.

"The tragedy as I see it is that by being so timid in our current renegotiation stance, we are throwing away a huge opportunity which would benefit everyone," the businessman argued. "I believe not only that it is in the UK's interest for our relationship with the EU to be re-forged, but it would also be very much to the benefit of the other EU member states for this to happen too.

"This is where I think we ought to be, and this is why, I think that we need to seize the opportunity to leave the existing arrangements and then to negotiate new ones along the lines which would work much better than those we have at present – not only in our interests but also to the long-term benefit of the other EU nation states too."

The comments from Mills come after Vote Leave, one of the two major campaigns calling for a Brexit, launched on 9 October. The group's backers include Mills, Conservative donor Peter Cruddas and billionaire Phones4U founder John Caudwell.

The organisation, which is run by lobbying supremo Matthew Elliott and former Michael Gove special adviser Dominic Cummings, is vying for the "leave" campaign designation from the Electoral Commission. Leave.EU, which has been set up by Ukip donor Arron Banks and has the support of Nigel Farage, is also hoping to become the official Brexit campaign.

'Pro-EU patriotism'

The groups are up against the pro-EU Britain Stronger in Europe group, which is run by Labour activist Will Straw and headed by ex-Marks & Spencer boss Stuart Rose.

Rose launched the campaign on 12 October by claiming it was "patriotic" to campaign for the UK to remain within the EU. He also told attendees in east London that Britain's economy would be weaker outside the 28-member bloc.

"To claim that the patriotic course for Britain is to retreat, withdraw and become inward-looking is to misunderstand who we are as a nation," Rose said. "In this ever changing and very uncertain world we need to engage with strength. I will not allow anyone to tell me I'm any less British because I believe in the strongest possible Britain for business, for our security and our society.

"Those who want us to leave Europe would risk our prosperity, threaten our safety and diminish our influence in the world. We know our economy would take a hit, we just don't know how bad it would be."

The comments come as the EU referendum debate heats up in Britain but it could be two years before the historic vote is held as Cameron has promised to hold the referendum before the end of 2017. The prime minister is expected to back the "remain" campaign, however he has demanded that Brussels reforms its rules over immigration, ever close union and internal reform.