Bus passengers will be left waiting at the side of the road once vehicles are a quarter full to enable social distancing on board, a major operator has announced.

First Bus, which runs services across Britain, said drivers will begin counting the number of people getting on and off its vehicles from Monday.

The capacity of buses will be reduced by more than 75%.

We fully support the Government’s guidelines and urge passengers to only travel if their journey is essential

Once the new limit is reached, drivers will not allow anyone else to board, leaving passengers at bus stops hoping the next service will be quieter.

Passengers who are able to board will be directed to use seats at an “appropriate distance” from each other, according to First Bus.

Dave Lynch, chief information officer of parent company FirstGroup, said: “Since the Government’s announcements last week, we have been working round the clock to find ways to innovate so that on our buses we can ensure safe, socially distanced space for our passengers.

“We are immensely proud that we have been able to develop this new system so quickly.

“We fully support the Government’s guidelines and urge passengers to only travel if their journey is essential.”

Drivers will count passengers using a device added to their ticket machine, developed by Ticketer.

John Clarfelt, the company’s chief executive, said the “groundbreaking technology” will be “vital for drivers” as demand for public transport increases over the coming weeks.