Young Tomatoe Plants

Pondman01

can any one tell what's happening to the leaves as they are turning brown on them, they are 2 in a pot at the moment. 

Dovefromabove

They need separating and potting up ASAP. 

Have the leaves been splashed during watering?  That can cause problems like he ones in your pics ... it can cause burning as bright sunshine is focussed as if the droplets are a lens. 
Water on the leaves also creates the perfect conditions for bacterial problems to take hold ...  as can crowded conditions ... another reason for separating them. 

Pondman01

Thanks for the replie yes I did wonder about being 2 in a pot. Causing stress. The leaves did get wet. I will get them sorted out grown in my greenhouse. And all come on well till now.