How do I feed myself for £1 a day?

For some reason, perhaps caught in a moment of weakness or insanity, I recently agreed to "Live below the line".

For those who do not know, this involves living on just £1 per day, for five days.

At first thought, it appeared to be a surmountable challenge.

But now the dates are fast approaching and the challenge seems more real.

And I have encountered a rather large stumbling block.

Well, two.

No one has sponsored me thus far. 

If things stay as they are, I assume this makes me exempt?

I would feel a tad foolish doing this for charity having made them no money.

My second stumbling block is that I cannot think of a single meal that can be made for £1.

Yet I have to, somehow, make three per day for that price.

My mind has gone blank.

More than that; it has upped and left.

Likely to be found running downhill at full speed screaming "HELP".

My only thoughts at present are that I could have porridge for breakfast and rice for dinner.

I would not exceed my total shopping budget of five pounds, in this case.

Though I fear I would not make it through one day on this, let alone five.

Essentially, this is my (not very succinct) cry for help.

Any ideas/recipes/advice/support welcome.

How on Earth do I feed myself for £1 a day?