UKIP’s Nigel Farage has even suggested we should carry on funding the project but, with our net contribution to the EU running at around £8.5 billion a year, others including Tory frontrunner Andrea Leadsom are calling for Article 50 to be triggered immediately.
As soon as the process is started, Britain will have just two years to negotiate its exit from the European Union with other member states.
If the deadline passes without an agreement, the UK will simply cease to be an EU member overnight.
It can only be extended by the unanimous vote of all the remaining 27 countries in the bloc, with some experts predicting there may be little appetite to accommodate Britain post-Brexit.
And one exasperated senior UK official has admitted: “The honest answer is nobody knows how long this would take and we would all be making it up.”
Other Tory leadership candidates, such as Liam Fox and Michael Gove, have advocated delaying triggering legal talks with Brussels, during which time the UK would continue to foot its membership bill.