What insurance you need as a landlord in the UK is a short list, and each item on it comes from a named source. Setting it out that way separates the one thing statute requires from the several things a contract requires and the several more that are judgement.
Required by UK statute
Employers liability, from the moment anybody works for you rather than for themselves, to the statutory minimum limit, with a penalty for each day without it. Nothing else. The other statutory duties on UK landlords are about safety and paperwork rather than insurance.
Required by a UK buy to let mortgage
Buildings cover for full reinstatement against listed perils, held continuously, with the lender's interest noted. Lenders may also require notification of a change of tenant type. Breach allows the lender to insure and charge you.
Required by a lease or an agent, and judged by you
A lease on a flat puts the structure on the freeholder and may require you to hold liability cover. Letting agents commonly require property owners liability at a stated minimum. Above that: loss of rent, contents, tenant damage, rent guarantee, legal expenses and home emergency are yours to decide.
Questions people ask about what insurance do i need as a landlord uk
What is legally required in the UK?
Only employers liability, and only if you employ anybody. Everything else comes from a mortgage, a lease, an agent or judgement.
What will my lender require?
Buildings cover for full reinstatement against listed perils, maintained continuously, with its interest noted.
Do agents require anything?
Many require property owners liability at a stated minimum before they will manage a property. Ask before signing the management agreement.