Iain Duncan Smith has told Sky News current affairs programme, Murnaghan, that Brexit could happen before 2017 as he sought to clarify Prime Minister Theresa May's announcement on invoking Article 50, which would trigger the United Kingdom's exit from the European Union, on Sunday (2 October).
When asked by host Dermot Murnaghan why the UK should wait another six months given ongoing concern and uncertainty for British businesses, Duncan Smith explained: "This is a 'by' the end of March." He added "So there's every chance she'll be doing it earlier than that."
Duncan Smith said there were issues such as trading arrangements that needed to be "lined up" first, but said: "I hope and believe [we leave] quickly and out the exit door well within the two-year period."
The former work and pensions secretary welcomed the prime minister's announcement and said the focus must be to shape the exit around the three "key areas" of borders, income and legislation which voters had indicated concern about through the referendum outcome in June.
Asked whether the announcement simply indicated further delay by the government, Duncan Smith said it was necessary to start the process of repealing the 1972 European Communities Act now, so that it coincided with the symbolic gesture of invoking Article 50.
The former cabinet minister also said it was necessary to give consideration to the relationship the UK has with the EU, post-Brexit, and advised negotiations should focus on areas of common ground.
He cautioned negotiations should not get "bogged down" in discussions about remaining in the EU single market.
"It's quite patently obvious that the European Union is simply not going to be prepared to let us stay as members of the single market," he reasoned, adding: "We can't be half-in, half-out, we have to be out, but we want a good relationship with them afterwards."
Duncan Smith urged the UK Government to focus on areas where common ground could be found.
"Negotiate with them on things that they want – and they want to have clear access to the UK market," he said. "That's where we now have a meeting of minds."
Speaking about UK businesses' concerns about leaving the single market, as indicated by car manufacturers last week, Duncan Smith argued there was no real guarantees offered by the single market.
"The single market is not really a free market, it's a managed market with very heavy levels of regulation that all of British Industry – whether or not you export - has to comply." He added: "Only about 10% actually export."
Seeking to allay such fears, he argued given the high volumes of UK exports to European member states, the EU would be unlikely to ruin a history of mutually beneficial trade transactions through the application of damaging tariffs.