I’m in rent arrears can I just hand the keys back and walk away
The landlord has rights and depending on the arrears and the state of the property and may well pursue you. The simple answer is you can, of course but, at your peril, as legally you should give notice
There is much case law in favour of the landlord. If you are in a periodic period of the tenancy you are far better off giving the required notice and leaving rather than staying and running up more and more arrears.
In one court case the tenants had held a periodic assured shorthold tenancy under the Housing Act 1988, but became behind with their rent. They surrendered the keys to the landlord and promptly left the property. The landlord brought legal action against the tenants for rent arrears, damage to the property, and rent in lieu of notice. The case concerned tenant's notice to quit during periodic tenancy. It was confirmed that common law position applies to this situation & tenant liable to paying rent in lieu of notice.
The Court held that there is an obligation on the tenant to serve notice to quit if he wishes unilaterially to determine (terminate) a periodic tenancy. The law requires that any tenant must give formal notice in writing to the landlord; the requirements for such notice must be in writing, must expire on the last day (or the next day) of the tenancy period, and must be not less than one calendar month for a monthly tenancy (four weeks for a weekly tenancy). Further, the Court held that delivery of the keys to the landlord does not constitute surrender of the tenancy unless the landlord accepts and agrees to the surrender. "The posting of the keys cannot have constituted more than an offer to surrender that the landlords were free to accept or reject"
The Court of Appeal awarded the landlords damages on all three counts (the tenants had defended the action on the basis that having surrendered the keys, no notice was required to leave the property).
So think very carefully before you decide what to do.