Tenant refuses to vacate at the end of tenancy, and doesn't pay rent.  Can landlord cut off the electricity to the apartment after warning?

Where I live (USA) that would be called an illegal eviction. Surely you have a court system there, too?

No, that would be illegal of course.

I don't know if your laws in the UK are similar to ours regarding tenants, but in the US you absolutely CANNOT cut off utilities to force eviction. 

Nope, you can't shut off anything, change the locks, etc.  You have to go to court to get them out.

You sound like an American or you are certainly using American terminology...which suggests this is not a real question

UK: Reality is it is very unlikely any landlord would offer a 5yr residential contract.

A flat or bedsit is British terminology.

Landlord has no control of tenants electric, the utilities accounts are in the name of the tenant

Landlords do not give eviction notices

............and a landlord has to give the required and correct number of weeks/months notice of non renewal and 'if' they happened to give out 5 yrs residential tenancy agreements...the notice period will depend on which country of the UK

In the whole of the UK notice to leave/non renewal and if they remain application to the court for the court issue an  eviction notice.... if the tenant doesn't leave on the date of the eviction notice, the landlord has to apply to the High court which will apply the civil court eviction and  court bailiffs will be appointed turn up 1-5 weeks later and remove the tenant, if the landlord also applied for unpaid rent ( up to court date) they will also collect the money by way of cash/card payment and/or taking the tenants possessions, like car, TV, PC, designer goods, furniture, they are auctioned money goes to landlord

Regardless of rent not paid the landlord is legally obligated to behave as a landlord, so any requests for repair by a non paying tenant legally has to be done, otherwise the landlord is breaking the law AND no judge will give the landlord an eviction notice...so the teant will continue to remain in the property and still no rent.... and the landlord is likely to get an order from the local council private housing officer to get any repair/ maintenance done by x date, or the landlord will be taken to court by the council...and in all this time the tenant has lived another 6-12 months in the property without paying rent

No you cannot do anything that would harass the tenant

You will be breaking the law. 

You will have to go through a legal process and ultimately get

them legally evicted. If you threaten or harass them

in any way the court will not consider you a responsible landlord and it will just prolong the sitution.

The tenant will probably be aware of all the legal loopholes

and dig their heels in until the bailiffs come! It is not fair but the law seldom is.

Tread carefully and don't loose your cool !

I am in the U.S..... but I have to assume laws are similar everywhere. You CANNOT shut off utilities, or otherwise harass a tenant. You need to post eviction notices, than after the time period required by law, go to the court for an eviction order. I would highly recommend hiring an attorney who deals with rental issues, as anything you do in violation of the laws may find you fined, not having a legal eviction, or the tenant being allowed to stay.