In a statement NatWest said: “As a responsible lender, NatWest places a strong focus on affordability and measures to safeguard its customers.
“This change of policy is being introduced to create greater consistency between buy-to-let and residential lending policy.”
The maximum LTV for buy-to-let mortgages will remain at 75% as will the maximum loan size of £500,000. All other remaining criteria remain unchanged.
The new policy, which comes into effect on Monday, will also be introduced for buy-to-let mortgages from RBS Intermediary Partners and RBS and NatWest mortgages available through the retail channels.