The future king - Colonel-in-Chief of the Mercian Regiment - wore his full military uniform for the visit to Tapa Camp in Estonia as he took part in a trench warfare exercise

Prince William, wearing fatigues and a beret in his role as Colonel-in-Chief of the Mercian Regiment, attended ceremony marking the start of their six-month deployment in Estonia as they take over from the Royal Dragoon Guards.

If royal visits are about sending a message, then the picture of the Prince of Wales in a tank near the Russian border must be one of the most direct. Prince William has come to Estonia to support UK troops in what is now the British Army's biggest operational deployment overseas, defending the Baltic state from the threat of Russia.