Campaigners camping out in tunnels in central London have been warned “they are putting themselves in even greater danger” by not leaving as weather conditions worsen.

Members of HS2 Rebellion, who have constructed the tunnels under Euston Square Gardens, claim the small green space near the station will be built over with a temporary taxi rank before being sold to developers as part of plans for the high-speed railway

HS2 Ltd said in a statement on Saturday: “In the past 24 hours the weather conditions have worsened and further heavy rain and sleet is forecast, which could lead to the tunnel becoming even more unstable.

“We are concerned that the occupants of the tunnel are now impeding efforts to help them, shutting themselves off underground, and preventing us from checking air quality as we supply them with air.”

They added: “As carbon dioxide can build up in the tunnel, they are putting themselves in even greater danger.”

They called on the campaigners to leave the tunnels as further rain is predicted throughout the weekend.

On Saturday, cherry pickers were at the Euston site as evictions continued, this time focusing on the scaffolding structure erected by campaigners.

On Friday, the protesters said “liquid mud” was pouring into the tunnel system.

In a video issued by HS2 Rebellion on Friday, veteran environmental campaigner Swampy, real name Daniel Hooper, said: “There was liquid mud coming through the wall last night, the rain stopped and we informed them (bailiffs) of this problem.

“They said they were going to pump the water out, the rain has now stopped and loads more liquid mud is coming down now.”