Failure to prepare for a no deal Brexit makes Britain look fretful, weak and incompetent, Jacob Rees-Mogg warned last night.
The prominent Eurosceptic said the Government appeared to be trying to frighten voters into accepting further compromises.
His intervention came as ministers faced a backlash over reports that the Army could be put on standby to deal with the fall-out if Britain leaves without a deal.
There was further Eurosceptic anger yesterday after it emerged that 70 technical notices on planning for no deal will be released on a single day at the end of next month, shortly before MPs return to Westminster.
Mr Rees-Mogg, chairman of the European Research Group of Tory MPs, said ministers were using scare tactics to bolster support for the Prime Minister’s Chequers deal.
Prominent Eurosceptic Jacob Rees-Mogg has said the Government appears to be trying to frighten voters into accepting further compromises on Brexit
‘The PM has said for a long time that no deal is better than a bad deal,’ he added. ‘If the Government cannot now show that it can deliver a workable deal based on WTO terms then it is not competent.
‘It is not a good look for the Government to appear fretful, weak and incompetent, but this seems to be the way it is approaching the idea of leaving on WTO terms.’
On the use of the Army, one minister told the Sunday Times that this was common in civil contingency planning, adding: ‘That’s not frightening the horses, it’s just being utterly realistic.’
But a source familiar with no deal planning at the Department for Exiting the EU said there had never been any discussion about calling in troops, suggesting the briefings came from standard civil contingency plans drawn up over many years by the Cabinet Office.
Ministers had planned to release a series of low-key technical notes over the summer setting out preparations for the possibility the UK could leave the EU without a deal in March next year.

He also claims ministers are using scare tactics to bolster support for the Prime Minister’s Chequers deal (former cabinet pictured during negotiations at Buckinghamshire retreat)
But Government sources last night said the documents were likely to be released together in late August.
Steve Baker, who resigned as a Brexit minister over the Chequers plan, said there appeared to be a deliberate attempt to undermine public confidence in the credibility of a no deal departure.
Mr Baker said last night: ‘I am deeply concerned by the Government’s communications strategy around no deal.
‘As I said to the PM I wanted to see the credibility and feasibility of our plans reinforced to the public in order to give reassurance.
‘Instead we seem to be seeing long-standing civil contingencies plans being trotted out in the run-up to dumping out a string of technical notices on a single day, shortly before MPs return to Westminster.
‘This doesn’t seem to me a sincere way to make the unwanted scenario of a no deal exit a credible and feasible proposition.’
Mrs May’s chief Brexit adviser Oliver Robbins, the architect of the Chequers plan, is also accused of trying to kill off the option of leaving without a deal.
Reports claimed that he has refused to highlight the substantial impact a no deal Brexit would have on EU economies during discussions with Brussels, despite a Government assessment finding the overall cost to the EU would be ‘far greater’ than that to the UK.
‘Robbins simply refused to raise it,’ a source said.
One insider told the Daily Mail that the Department for Exiting the EU had drawn up plans for an advertising campaign on the continent highlighting the dangers of a no deal Brexit for key sectors of the European economy such as farming and cars – only to have the idea blocked.
Government sources last night denied there was a deliberate attempt to scare voters into accepting the Chequers plan.
One source said the delay in publishing the technical notices was because they were not yet ready, rather than an attempt to influence MPs as they return to Westminster after the summer.
‘This is not Project Fear,’ the source said. ‘Project Fear was a series of predictions about things. This is a very pragmatic look at things that need to be done if we arrive at a certain outcome.
‘We remain confident that we will reach a good deal.’
In a boost to the Prime Minister’s chances of reaching a deal, it emerged over the weekend that Brexit has been put on the agenda of an informal EU summit in September.
Downing Street said Austrian chancellor Sebastian Kurz agreed that Britain’s departure from the EU would be discussed at the European Council meeting being hosted by his country, which currently holds the EU presidency, on September 20.
That could allow Mrs May to prepare the ground for an October meeting of EU leaders where the details of the future relationship would be thrashed out.