Members of the Royal Tank Regiment have been testing their cold-weather capability on Exercise Winter Camp on NATO's eastern border.
As part of the UK military's ongoing commitment to supporting Estonia's military, they have been training alongside their counterparts in the Baltic State, testing out their own capability in sub-zero temperatures.
While both sides get useful training from this – it is also a sign of the long-held bond between the British and Estonian military, with UK forces maintaining a constant presence in the country since 2017.
About 350 troops from the UK and Estonia are taking part in the training, alternately splitting into attacking and defensive teams to attempt to take the road that cuts through the trees.
It is a rare chance for the Estonian troops to work with the Challenger 2s of the Royal Tank Regiment, giving them an insight into the tactics used by UK forces and developing their own skills.
The British forces are also benefiting from the chance to develop their ability to operate in inhospitable sub-zero temperatures.
As Russian forces continue to build up alongside Estonian borders and pose a threat to NATO's eastern members, collaborative training is vital in ensuring the allies can operate effectively alongside one other.
Watch: Estonia welcomes reports of additional deployment of UK troops.