UK average mortgage rates have risen back to the level of a month ago as renewed tensions in the Middle East feed through to homeowners. Lenders' funding costs have increased as markets judge that a prolonged conflict reduces the possibility of interest rate cuts by central banks. The five biggest High Street banks are among a host of lenders which have increased their interest rates on new fixed deals in recent days. Mortgage rates had been falling as a ceasefire between the US and Iran initially appeared to hold. Oil prices hit $100 a barrel for the first time since May on Thursday after several days of increases, stoking fears of higher inflation and a lower likelihood of interest rate cuts.