The answer will depend on the lifestyle you want in retirement. Even if you own your own home, you'll still have regular bills like:
- house - council tax, gas, electricity, water and food costs (which are easily £200 per week or more now and I can't imagine they'll be any cheaper in the future). Regular household maintenance costs.
- communication - mobile phone/landline, plus tv and streaming services
- transport costs - If you run a car, that's even more outgoings (MOT, petrol/electricity etc). If you don't have a car then you'll have public transport/taxi costs.
- Insurance - you'll still need home and contents insurance, you may be paying Life Assurance or other insurances like private medical insurance.
Then if you don't want to just live in your house and walk everywhere, you have to factor in some of the things that actually make life enjoyable, like eating out, meeting up with friends, buying a takeaway coffee, going on holiday (plus all the costs that go along with it, like travel insurance etc), entertainment like the cinema or clubs.
You'll also need an emergency fund for replacing things like washing machines, dryers, cookers etc., when they reach the end of their usable life. You may want to pay someone to do the cleaning.
That's actually quite a lot for £800 per month to cover. If you have no money, you have no money, you have to work with what you've got. So although it may be possible to live on the state pension, for me, it wouldn't be possible to live well and certainly wouldn't be possible to do the things I enjoy on that amount.