It is a skill treasured by drinkers and passed down the generations, requiring pinpoint planning, nimble footwork, subtle eye contact and the occasional well-timed shove.

But traditional tactics for getting served first in the crush at the bar could be consigned to history if a London pub’s trial of facial recognition scanners is a success.

The software, more commonly used by police and airport security, has already been trialled at the 5cc Harrild & Sons cocktail bar in the City.

An internet-connected webcam equipped with face scanners keeps tabs on new arrivals, with each customer assigned a number flashed onto a screen telling the bartender who is next.

The technology, invented by data science experts DataSparQ, is also said to help speed up ID checks as the computer “knows” if a customer looks under 25 by scanning hundreds of biometric data points.

Future planned features include a “FaceTab”, where a customer’s features are stored so they can rack up a tab without needing to hand over their credit card.

Top tips for not annoying bar staff Don’t annoy bar staff by complaining if you’re not served first — this is their manor, not yours. Mind your Ps and Qs — a smile and politeness go a long way with these workers, many of whom are on minimum wage. Know your order and have your money ready — whether paying by cash or card — to prevent delays. But don’t flash the cash — it’s annoying and patronising to wave a tenner in their direction to get eye contact. Bring your glass back to the bar — yes, there are glass collectors, but it will earn you brownie points.

It can also be scaled up for use at large events such as music festivals to “place drinkers in a dynamically intelligent queue”. John Wyllie, managing director of DataSparQ — which builds anti-fraud machine learning software for insurance firms — said: “We are in talks with pub owners to roll out the technology nationwide in the next year.

“We are expecting it to start in bars and progress to music festivals.”

The inventors have implemented measures to reduce the fears of privacy advocates, saying all data is wiped after closing time.

Mr Wyllie added: “When each session ends, as well as the IDs and images being deleted locally, they are also deleted from the cloud. Nothing is ever permanently stored and cannot be cross-referenced anywhere else.”

Harrild & Sons barman Luka Kovijanić said: “It enables us to maximise our pouring potential and cuts out the need for sharp elbows. The regulars still moan about the price of a pint but now they can’t moan about who’s next in line.”