Government bills are short dated securities which the government use to finance its public debt.
Treasury bills are issued by the Government. Bills don’t have an interest rate, but, allow the buyer to repurchase at a discount and this discount is the effective interest rates.
Because bills can easily be traded in at any time, they are seen as liquid assets (near money). This contrasts to bonds which are seen as illiquid.
Movements in the base rate, are unlikely to have a significant impact on the price of short term bills.