An ambitious mission to drill through 3km (1.8 miles) of Antarctic ice to a lake that has been sealed off for thousands of years has been cut short.
The team at Lake Ellsworth decided to call off the mission in the early hours of Christmas Day UK time.
They were unable to join the main borehole with a parallel hole that was to be used to recover drilling water.
The team is now "weatherising" the equipment and it is unclear when they will be able to resume the project.
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Once back on UK soil, the team will have to develop a report on what went wrong, and only then can the thought of a return trip be considered.
"It will take a season or two to get all of our equipment out of Antarctica and back to the UK, so at a minimum we're looking at three to four, maybe five years I would have thought," Prof Siegert said.
But he remained hopeful about the future, and said that this year's mission was far from a complete loss.
Lake Ellsworth Antarctic drilling project called off