What are the UK’s ‘fiscal rules’ and why is the OBR under attack?

The Treasury watchdog is seen by some Tories as a block to tax cuts - and could be ignored by Jeremy Hunt

It has been described as a millstone around the chancellor's neck and the reason Conservative MPs could be disappointed by Jeremy Hunt's budget on Wednesday if he spurns their demands for large pre-election tax cuts.

After coming under intense criticism during Liz Truss's premiership, the Office for Budget Responsibility (OBR), the Treasury's tax and spending watchdog, is once again under fire.