The Bank of England is expected to unveil the biggest interest rate rise since the 1980s on Thursday as it tries to control the runaway inflation which is battering British households.In a crunch meeting, the nine members of the Monetary Policy Committee will make a decision that could push up the amount that millions of mortgage holders have to pay their banks every month.The consequential decision is expected to push up the Bank’s base interest rate from 2.25 per cent currently to 3 per cent, the highest since 2008.