It is no secret that the buy-to-let (BTL) market has changed substantially in the last few years, with more and more tenants now spending longer in rental properties than they ever did in the past.

With a growing number of families - a demographic for which stability is an essential part of life - now renting rather than buying, it has meant more landlords are able to keep tenants for periods of years rather than months.

And now one leading lender is set to help facilitate this change in market conditions far more easily by offering owners a change in mortgage conditions.

Previously when landlords have bought properties for the specific purpose of letting them out, lenders have specified that they can offer contracts of no longer than 12 months. However, The Mortgage Works (TMW), a branch of Nationwide, has now revealed it is going to change this restriction and allow them more freedom.

Under new rules, landlords will be able to give tenants a contract of up to three years, giving a level of stability to both residents and property owners.

Richard Napier, divisional director of mortgages at Nationwide Group, said that with Shelter's figure of one-in-five UK families now renting rather than buying, it was important that the mortgage market moved to reflect the overall position of the renting sector that landlords now experience regularly.

He added: "The private rental sector has grown and changed phenomenally over the last few years, with rising numbers of families looking to rent in particular. We want our buy to let customers to be in a position to be able to meet the changing needs of the market."

It will mean a greater need for extensive landlord insurance products, however, as anyone who sees their home rented out for a longer period of time may find that it is more prone to damage or loss than in short six-month spells when they can conduct more inspections.