Serious tomato problem?

[Leeds_lad]

Having a major problem with one of my tomato plants, any help would be appreciated.
Seems to have only affected the lower leaves so far, but i reckon it is close to spreading. Basically the leaves and stems keep turning yellow, shrivel up and the whole thing eventually just falls off. The plant now has nothing from about the top 1/3 down, just the main stem. Whats happened, and what could be done to fix it?

[VirginVegGrower]

Sounds like a shortage of magnesium potentially if spreading upwards - spray with Epsom salts. I would do this away from any other plants to be on the safe side. Take it into house/sunny windowsill.

[Leeds_lad]

it's currently in the house and thank you i will try that

[Two_Sheds]

Has it been in the same small pot for a while? It might appreciate some new compost

[samseed]

Hi Leeds lad,i had the same problem a couple of weeks ago with my toms,they were about 3 inch high and yellowing from the bottom up,i gave them a leaf spray with epsom salts solution and 2 weeks later they like new,i also gave them a liquid manure feed last week and that really boosted them.Hope this helps