OK so now we've got an upstream wind. What's the rule? Keep the fly downwind. So that's where we've got to put it; downwind which in this case is upstream.

This is the scenario: true left bank, on the dangle, upstream wind, we want to roll cast across the current (up to 90 degrees - once again more is possible but there are better techniques available). Here's what we do:

• move your feet and face the direction you want to cast, now turn from the waist and face the line on the dangle

• make the lift, and then immediately, without stopping,

• sweep the rod upstream rotating from the waist, drawing a rising-crescent with the tip of the rod, finishing with a little flick of the tip.

  The fly will lift off the water, travel upstream fairly close to the water and 'kiss' the water surface upstream and slightly out from us. We are aiming to place the fly so that it is slightly to the outside of the final roll casting direction. If it lands downstream of this angle we must STOP everything and roll cast the line back down river and start again, otherwise we will hook ourselves.

  The further upstream of us that the fly travels - the less efficient the cast; remember that with the roll cast we want the rod tip to be travelling almost directly over the flyline. Some instructors recommend kissing the water surface with just the fly and leader, others recommend putting down a couple of feet of fly line - it all depends on what sort of roll caster you are: the more power you apply early on in the forward stroke - the more line you will need on the water.

  If the line doesn't kiss the surface we have failed to dip the rod at the start of the rising crescent. If the line lands and then flicks over itself we have dipped too much. If it doesn't travel upstream we have either been to gentle, or dipped to early. If we cast the fly too far up with the double-spey it doesn't really matter: we can let the current carry it back downstream to our chosen position. With the single-spey we don't have this option, because if we pause too long our D-loop sags and we end up with too much line on the water.

• Hopefully the sweeping stroke has done it's job and we have a correctly positioned fly and a nice D-loop. Now all that remains is the forward stroke on the roll cast.