Interest rates are the price of money. Its how much you have to pay to borrow money. If there is a lot of money in the system, interest rates are low, and vice versa.
Interest rates are also inversely correlated with price. For instance, if I buy a bond that pays 5% for $100 and tomorrow someone can lend money at 6%, no one is going to pay $100 for a bond that's paying only 5%. If they can lend money now only at 4%, they'd pay over $100 for the bond paying 5%.
BoE is going to be buying a lot of bonds, which means the price is going up (increase in demand) and others will pile in. And since price and interest rate are inversely correlated, that means yields (interest rates) are going down.
Similarly if interest rates go up, the bonds that banks and pension funds hold will go down in price (inversely correlated). But the downside is there's more money in the system, cheaper credit, more inflation and decrease the valuation of the currency relative to other currencies.
Interest rates are also inversely correlated with price. For instance, if I buy a bond that pays 5% for $100 and tomorrow someone can lend money at 6%, no one is going to pay $100 for a bond that's paying only 5%. If they can lend money now only at 4%, they'd pay over $100 for the bond paying 5%.
BoE is going to be buying a lot of bonds, which means the price is going up (increase in demand) and others will pile in. And since price and interest rate are inversely correlated, that means yields (interest rates) are going down.
Similarly if interest rates go up, the bonds that banks and pension funds hold will go down in price (inversely correlated). But the downside is there's more money in the system, cheaper credit, more inflation and decrease the valuation of the currency relative to other currencies.