[mo-jo]

I'm hoping to attach a picture and would appreciate it if any of you guys could tell me what it is.

Thanks

[mclarkuk1]

Im no expert but it looks like scorch to me.    Fingers crossed im right 

[mumofstig]

I'm not sure what it is but it's not blight.

There have been no blight outbreaks yet this year, it has been too dry for blight

Are there any insects on the underside of the leaves?

[Aunt Sally]

Did you give them a general purpose fertiliser when you planted them ?

It could be a mineral deficiency.

[Aunt Sally]

Possibly Magnesium

[mo-jo]

Thanks Guys, I'm glad its not the dreaded blight.  This is my first time growing anything so I keep panicking about stuff.  Paranoid everything is gonna die.

I didn't put any fertiliser in when I planted them but I do have some tomatoe feed, should I give them some of that?

[Sid]

Looks like magnesium deficiency, we had same problem last year not blight!

[Yorkie]

I didn't put any fertiliser in when I planted them but I do have some tomatoe feed, should I give them some of that?

No, tomato feed is high in potash.  A watering of epsom salts would do the trick.  There's another one which would also do but I can't remember its name 

[Aunt Sally]

I didn't put any fertiliser in when I planted them but I do have some tomatoe feed, should I give them some of that?

No don't use tomato fertiliser that's for growing fruit.  You want to grow tubers. 

If you don't have or can't get potato fertiliser just use a general purpose one like Growmore.

[Salmo]

Tomato fertiliser and potato fertiliser are almost the same so using tomato fetiliser would be OK. Both are high in potash.
e.g.
vitax tomato 5p - 2.5p - 8k
vitax potato  4p - 2.5p - 8.5k

Granulated fertiliser should have been added to the soil before planting. If it is applied now it is likely that only the nitrogen will be available to the plant.

However in this case I would agree with others and apply Epsom salts or a liquid feed that contains some magnesium, many of the tomato fertilisers do. The brown scars on the leaves will not vanish but new leaves should be green and shiny.