The National Rail app — famously conservative in its estimations of how long it takes to get from one part of London to another — suggests just one minute for a changeover between King's Cross and St Pancras railway stations.
Straddling the east and west sides of Pancras Road, the pair are literally a stone's throw apart (although we haven't put that to the test).
And their names are both totally representative of this shared area in which they find themselves; St Pancras being the older term for this part of London, but King's Cross arguably the more widespread (and notorious).
They even share a tube stop, for goodness' sake.
So why were these two grand old railway terminals built to be separate, rather than as some sort of integrated mega-hub?
For the answer, you have to go right back to the 19th century, to London’s early railway history.
King's Cross is the more senior of the two stations. Built by the Great Northern Railway, it opened in 1852. Quaintly, it had just two platforms then: one for arrivals, the other for departures.
Back in the early Victorian era, businessmen competed with one another to bring the railway to new parts of the country. (In fact, the Underground ended up being a microcosm of this, with different firms racing to build new lines across London.)
The Great Northern Railway would have seen the likes of the Midland Railway as a rival. Midland spent years borrowing platforms at King's Cross and Euston, before eventually pouncing on some land to build its own terminus. And that's why there are two separate stations.
And as to why they were so close, it was a simple matter of land availability in a rapidly-growing metropolis. The site chosen for St Pancras required a pretty brutal clearance process, but crucially, Midland Railway had a lot of help from the Government.
The job meant flattening houses in a district called Agar Town, as well as bridging Regent's Canal, ploughing through the St Pancras burial ground (a young aspiring writer named Thomas Hardy helped with the exhumations), and even moving a church to east London.
Along came St Pancras, opened in 1868. Five years later, George Gilbert Scott’s iconic hotel building was erected in an attempt to outshine King's Cross — not to mention Paddington and Charing Cross.
Scott's idea seemed too ludicrous to win the design competition — precisely why the rail bosses loved it so much.
So, every time you see his spectacular gothic-revival frontage, remember that it was born of a spirit of one-upmanship that prevailed during the age of industrialism.
And that's the same reason these two stations were built independently of one another.
That almost certainly wouldn’t have happened a century later, when the railways were collectively under government control. Indeed, an idea was mooted in the 1960s to merge the two stations, perhaps demolishing both. Only a campaign by John Betjeman saved St Pancras.
But disuse and dilapidation meant that station struggled through the late 20th century. The hotel was turned into office space, then fell empty. British Rail tried to sell off the old station clock but accidentally smashed it in the process.
Refurbishment in 2007 gave the station a new lease of life; it now hosts Eurostar, and its hotel is a hotel again. Even Thameslink services were re-routed from King's Cross to a pair of new platforms under St Pancras.
St Pancras got Paris. King’s Cross got Harry Potter. Safe to say there's life in that old rivalry yet.