Can anyone help I.D this potato leaf problem?

I found a couple of leaves like this when I went down the plot this evening and cannot find any pictures on t'internet to help me identify what it might be, does anybody here have an idea and should I be worried???

looks like natural die-back to me. The plants are coming to the end of their life. How are the potatoes? and what type are they?

They are Kestrel, planted 19th April, so they've been in the ground nearly 13 weeks, but I was under the impression they'd be in 18 weeks.

I had that on all of my Kestrel plants.  After checking on some previous threads I took it that it was likely to be a magnesium defficiency.  I treated with epsom salts but I think I left it too long to administer the treatment and it got worse very quickly.  A friend on the plot advised that I should cut the plants down and dig the potatoes up as and when I wanted and when the row was empty, treat the soil with epsom salts and then add home made compost over the autumn which should sort it for next year.  I treated my Cara row at the first sign of these leaves and it seems to be much better now.

they are earlies so time to lift them. Pick a dry day (ha!), dig them up and let them dry off for a couple of hours in the fresh air then store in paper or hessian sack. You can leave them in the ground and dig them up as you need them but you then risk loosing some to the slugs.

Second earlies officially, so was hoping to leave them to mature as a maincrop, which is sort of what I did last year (my first), however I planted them mid May then so they never reached the 18 week point.

Re the slugs, they are pretty resistant to them - not 100%, but much more so than the Wilja I also grew last year.

I might dig one up to see what sort of size they have reached.  Thanks for the feedback though.

magnesium deficiency treat with trace element spray but to late for your kestrels as they are ready to dig anyway eddie