UK Royal Navy personnel have participated in the Nato-led Bold Monarch, the world’s largest submarine rescue exercise, in Spain.

The ten-day exercise aimed to test the ability of allied teams to react to submiss and subsunk responses.

The exercise focused on the western Mediterranean, with four submarines from Portugal, Spain, Turkey and Russia participating.

During the exercise involving navy personnel from 13 countries this year, vehicles from Italy, the US, Russia and Sweden rescued the submarines.

The exercise, in which Russia participated for the first time this year, takes place every three years with the next scheduled for 2014 in Poland.