A couple of pointers:
1. If staff are working for you for the majority of their income then they have to be classed as employed not self employed and you'll need to pay NI and holiday pay for them. Unless you're going to be a cowboy and try and fiddle the taxman!!!

2. To employ someone full time, trusting them with the money and hoping that they are going to be honest with declaring all the work to you, you'll need to be paying them a decent wage.
3. In order to pay a decent wage then you'll need to have a decent round, minimum £2K/4 weeks/person which will not fall on your lap from day one.
4. After paying a wage, the money that's left isn't your profit, you'll have insurance, equipment, fuel, van, accounts, tax, etc, etc to pay out of all of that.
5. Due to the current economic climate, EVERYONE who has been made redundant in the past 5 years now thinks they can be a window cleaner, many are investing £,000s in vans and WFP equipment. I spoke to a guy just the other week in Darlington who'd spent £22,000 of his redundancy money on a new Thermopure van and he hardly has any work for it, because of the hype the manufacturers put on selling he expected to be flat out from day one................eh, no, get real!
Tosh is right, it can be done, but more likely only if you buy a business that is already established.
You can have mine if you want..............£300,000