Take a left turn here on the B6318 and after 6 km (4 miles) you will see the sign for Birdoswald.
There aren't any roads to Biroswald, are there?
mnli hypothesis: There aren't any roads to Biroswald, are there? premise: Take a left turn here on the B6318 and after 6 km (4 miles) you will see the sign for Birdoswald.