A giant foaming 'sinkhole' spewing out "alien" foam has appeared on a rugby pitch where HS2 is being built.<br /><br />Work on the project was stopped for several hours after dog walkers found the brown foam bubbling out the ground at Ruislip RFC in west London.<br /><br />According to HS2, workers moved to seal off the area which was “most likely caused” by one of the tunnelling machines passing through a small pre-existing borehole.<br /><br />Jatin Radia, 45, chairman of Ruislip RFC, described the bubbling pool as “alien” and added: “I was watching his 14-year-old son play NFL on Saturday morning when my phone started blowing up.”<br /><br />“Members of the rugby club were sending me photos and videos asking me what was going on.
