The Prime Meridian that divides the eastern and western hemispheres of the earth is apparently 102m to the east from where it is marked in south east London.
The actual location of the famous dividing line is not, scientists say, the point visitors flock to stand on at the Royal Observatory.
Instead, GPS technology suggests it cuts across a footpath in Greenwich Park near a bin.
According to a newly published paper visitors “must walk east approximately 102m before their satellite navigation receivers indicate zero longitude”.
The Royal Observatory’s public astronomer Dr Marek Kukula told The Independent that staff were often questioned by tourists “helpfully pointing out that our meridian is in the wrong place”.
He said: “We’re forever telling this story, making the point that as we refine our measurements and get better technology, of course these things change, because we want to have the best possible data.
“I think having a marker in the park would be brilliant, to update the story of the Greenwich meridian line into the 21st century. At the moment the nearest thing there is to a marker is a litter bin.”
The line, which is used to define Greenwich Mean Time, was calculated by pointing a telescope directly upwards at a so-called clock star.
However, the calculations would have been slightly wrong due to the shape of the Earth, so it makes sense that measurements taken using GPS systems would show a more accurate picture.
Entry to the Royal Observatory, which includes the chance to stand on the official marker is £9.50. There is no charge for standing beside the litter bin in the park.