Footage of platforms packed with commuters piling onto the London Underground has again emerged, raising questions about the safety of key workers.

The images were taken on the Jubilee Line at East Ham on Monday morning, as rush-hour traffic congestion hit its joint highest level since England's third lockdown began.

Union bosses have called on sites to stagger opening times to even out traffic, or for the congestion charge to be suspended for their workers.

Despite concerns over the current surge in the virus, work in industries such as construction and manufacturing has continued during recent months in all four nations of the UK.

Forty chief executives of London's biggest contractors met with Government officials in an emergency summit last Friday to discuss the issue.

Finn Brennan, ASLEF's district organiser for the London Underground, told BBC London: “I don't think anyone gets on the Jubilee line at 7am in the morning for the laughs.

“The problem is there are people who have no other choice besides going to work, they don't have the option of working from home, they don't have the option of furlough, and there are some locations where people are coming onto the Underground all at the same time in the morning, when for the rest of the day the system's actually really quiet. 

“The problem is, unless these pinch points are dealt with, then we are going to have to see services withdrawn and stations closed, because people are travelling in a way that is not safe for them, and is also not safe for the staff who have to deal with them and would have to deal with any incidents.”

TfL told MailOnline Monday saw 18 per cent of normal demand on the Underground up until 10am - the same level as the week before.

Nick Dent, London Underground's director of line operations, said: “We are doing everything we can to help ensure those who need to travel for legally permitted reasons are able to do so safely and maintain social distancing, including targeted communications to encourage people to travel at quiet times. 

“West Ham and Canning Town are the busiest stations on our network early in the mornings, and we are working with Newham Council to look at how working patterns in the borough could be changed to help ease any crowding during busy times. 

“We have also urgently contacted large employers in the area including Amazon, Sainsbury's and Royal Docks to urge them to stagger shifts and operating hours to enable those who have to travel to work to do so in the quieter times. 

“In addition, we have sent advice to business groups, and to construction companies and the supply chain through Build UK. We are regularly meeting with the trade unions to work together and respond to their concerns around this issue.”