When Caesar invaded England in 55BC he gave us our first weather report for this country. He tells how his fleet of 100 ships sailed across the Channel in fair weather, and when the cliffs of Dover came into sight the English warriors were waiting on the clifftops ready for the invaders. So the Romans sailed farther up the coast looking for a safe landing place. They found flat open beaches near Deal or Walmer on a falling tide and established a camp on August 26-27.

A team of astronomers re-enacted the landings in August 2007, in a rare opportunity when the lunar cycle and alignment of the Sun and Moon gave tidal conditions that coincided closely with those that Caesar had experienced – such an alignment would not occur again until 2140. But they found that the Channel was flowing the wrong way on those dates. However, exactly the right conditions for the safe landing happened four days earlier, on August 22-23, giving a revised date for the Roman invasion.

The safe landing did not help Caesar, though. Four days later, “such storms ensued that the task [of fighting the English] was of necessity interrupted”, he wrote. In a high tide and a storm surge the Roman ships were battered, and Caesar brought his army back to Gaul.