OK you want to be very careful right now about 100% mortgages.
I don't for a moment think that there will be a crash but there could well be a drop in value in some areas especially if interest rates go up further.
If this happens where you are you'll be in the situation of owing more than the place is worth (negative equity) which means that you'd probably be stuck with the property as you couldn't sell it for enough to pay off your lender.
If there's a rise in interest rates or a change in your circumstances and you can't keep up with the mortgage you'll be stuffed.
Remember it's not just the mortgage, there's council tax, heating, electricity, water rates insurance.
At an introductory 6% that's only �270 a month but that's �360 at 8% and if it were to hit 12% that'd be �540.
Personally I'd rent for a while and save a bit for a deposit, if you find it hard to save you'll find it hard to afford a mortgage