We're getting a bit philosophical, Corby.
The definition of "poverty" in this country is ridiculous. Using a comparative measure of less than 60% of median earnings will almost always see people in poverty, unless the government legislates to ensure that nobody can have an income lower than that.
So, in the UK (or more particularly London, as this question mentions it specifically), shelter would be some sort or permanent or semi-permanent home large enough to accommodate all those living in it. Warmth would be the ability to keep the place at about 18 degrees C during waking hours. Food and drink would be sufficient to remain healthy. Drink would not include alcohol. People who cannot afford alcohol are not necessarily in poverty.
If you can afford those things you are not, by my definition, living in poverty. You may not be well off; you may even be poor. But you're not in poverty.