The Bank of England may run two inflation measures side by side when setting interest rates under plans still being finalised by the Treasury.

Gordon Brown has said he will change the bank's inflation target from the current retail price index excluding mortgages to the harmonised index of consumer prices "at the time" of the November pre-Budget report.

Mervyn King, the new governor, has raised doubts about such a move.

The latest figures showed there was a gap of 1.6 percentage points in July - close to the widest gap between the two measures since HICP was launched.