The Tory civil war on Brexit exploded into public today as Boris Johnson tore into Theresa May's post-Brexit trade plans.
The Foreign Secretary branded the proposed customs partnership 'crazy' and claimed it would create 'a whole new web of bureaucracy'.
Mr Johnson warned it would not meet the key test of Britain 'taking back control', and would restrict our ability to strike trade deals.
The dramatic intervention, in an interview with the Daily Mail, raises the prospect that Mr Johnson could quit if Mrs May does not drop the plan.
It sparked a swift backlash from Tory Remainers, who raged that Mr Johnson's stance was 'disgraceful' and he must 'wake up to reality'.
Amid mounting pressure on Mrs May to find a way through the impasse, leading Tory Eurosceptic Jacob Rees-Mogg also said Britain would be much more 'aggressive' in negotiations with Brussels if Mr Johnson was PM.
Brexiteers fear No10 wants to 'rebadge' the customs partnership blueprint and force it through despite heavy criticism from a powerful Cabinet subcommittee last week.
But Mrs May has pushed the 'War Cabinet' showdown back from this Thursday to next week as she struggles to find a compromise solution.
Under the partnership concept, officials would track shipments into the UK and collect tariffs for Brussels on goods ending up in the EU.
Mr Johnson said this would simply lead to more red tape.
'It's totally untried and would make it very, very difficult to do free trade deals,' he added.
'If you have the new customs partnership, you have a crazy system whereby you end up collecting the tariffs on behalf of the EU at the UK frontier.
'If the EU decides to impose punitive tariffs on something the UK wants to bring in cheaply there's nothing you can do.
'That's not taking back control of your trade policy, it's not taking back control of your laws, it's not taking back control of your borders and it's actually not taking back control of your money either, because tariffs would get paid centrally back to Brussels.'
© Associated Newspapers Ltd.