Homeowners should be wary of cheap two-year fixed mortgage rates, according to one company of mortgage brokers. Changes to the economy caused by Brexit may make it preferable to lock in a good rate for longer. Even if interest rates stay low, economic instability may cause lenders to tighten restrictions on who may borrow money. This would put people at risk of only having expensive options when a short term fixed rate comes to an end. A five-year fixed rate or a lifetime variable rate may prove to be a better deal, depending on conditions if moving house later.