The foreign secretary has compared issues over the Irish border with implementing the congestion charge in London.
Boris Johnson made the comments as he dismissed concerns that leaving the customs union could lead to a hard border between the two countries.
In what he called a "very relevant comparison", Mr Johnson told the BBC's Today programme "there's no border between Camden and Westminster" adding the congestion charge was put in place without any need for border checks.
There are fears the 1998 Good Friday Agreement, which brought the decades-long sectarian conflict in Northern Ireland to an end, could be put at risk should Brexit lead to a hard border between Northern Ireland and the Republic of Ireland, which is a member of the EU.
The London congestion charge does not require checks on the road, and is enforced with electronic surveillance.
The Foreign Secretary said: "We think that we can have very efficient facilitation systems to make sure that there's no need for a hard border, excessive checks at the frontier between Northern Ireland and the Republic.
"There's no border between Islington or Camden and Westminster, there's no border between Camden and Westminster, but when I was mayor of London we anaesthetically and invisibly took hundreds of millions of pounds from the accounts of people travelling between those two boroughs without any need for border checks whatever."
Interviewer Mishal Husain said: "Come on, you can't compare two boroughs of London with the kinds of difference in the arrangements that would be in place after Brexit between the UK and the EU."
Johnson responded: "It's a very relevant comparison because there's all sorts of scope for pre-booking, electronic checks, all sorts of things that you can do to obviate the need for a hard border to allow us to come out of the customs union, take back control of our trade policy and do trade deals."
He also suggested Jeremy Corbyn's proposal for a new customs union with the EU is "advocating colony status" for the UK.