Moreover, even if short-term interest rates were raised, long-term interest rates would not necessarily rise, so that the spread between short-term and long-term interest rates might actually decline.
This is currently happening in the United States and has happened in Japan since 2006.9  The reason many market participants think that the yield curve will steepen and hence the term spread will increase when the Bank raises interest rates is probably that they expect the opposite to happen of the flattening of the yield curve seen at the time the Bank introduced the negative interest rate policy on January 29, 2016.