As the measure is considered at its final Commons stages on Monday, eurosceptics accused the government of trying to slip through a change that could allow David Cameron to hold a snap referendum one month after finalising his EU negotiations.
The eurosceptics were already planning to challenge ministers over their apparent U-turn on the rules on government activity during the final phase of the EU referendum campaign.
Steve Baker, a leading member of the Conservatives for Britain group, said that the government appeared to be giving itself leeway to use the Whitehall machinery in the last four weeks of the campaign known as purdah period. Baker is alarmed by government plans to allow itself to bring forward regulations to modify the purdah section of the bill.
The eurosceptics have now spotted a small wrinkle in the amendments to change the process for the designation by the electoral commission of the formal yes and the no campaigns. Eurosceptics fear that Cameron would like to use the momentum from a successful renegotiation of the terms of Britain’s EU membership to hold a referendum as quickly as possible.
The amendment could, the eurosceptic sources say, pave the way for a snap referendum within a month, rather than the usual 10 weeks set out in the original legislation covering referendums, which dates back to 2000. Sources say the amendment would split the designation process from the usual 10-week referendum timetable.
The change could mean that the electoral commission, which argues in favour of 16-week campaigns, could be forced to designate the campaign groups after the bill enters the statute book but before the prime minister has set the date for the poll. This would hand Downing Street the sole power over the timing of the referendum.
One leading eurosceptic source said: “The only thing stopping you having a four-week referendum period would have been that designation process. So they have removed the only legal obstacle left for making it a four-week referendum. The only way you would argue that you needed to do that in the method you have chosen is because you wanted to have a very short referendum.”
The fresh rebellion came as Liz Kendall is to warn that Jeremy Corbyn’s equivocal approach to the EU could jeopardise Britain’s membership if he wins the Labour leadership.
In a speech on Thursday, Kendall will say: “I am increasingly concerned about the attitude of some on the far left, including Jeremy Corbyn, who prevaricate about our membership of the European Union at every opportunity. We cannot allow David Cameron to reduce the question of our continued membership of the EU to a debate about whether or not Polish workers get tax credits. And we must not allow the far left to argue that the EU is somehow against the interests of ordinary working people, when the reality is that Europe is vital for jobs, trade and investment, and for social rights and protections too.
“Of course Europe needs to change. The European Union’s failure to respond quickly and effectively to the refugee crisis, and the ongoing problems within the eurozone and the Greek economy make that abundantly clear. But if focus on problems rather than benefits we will fail to win argument.
“The answer is for Britain to help lead the debate within Europe about how we address these challenges, which simply cannot be dealt with by any one country in isolation, rather than withdraw to the sidelines or out of the European Union altogether. I’m proud to be the most pro-European candidate in this leadership race. Labour cannot equivocate. It’s time for leadership: ‘maybe’ won’t be on the ballot paper.”
This article was written by Nicholas Watt Chief political correspondent, for theguardian.com on Sunday 6th September 2015 22.37 Europe/Londonguardian.co.uk © Guardian News and Media Limited 2010