A Constitution can be ignored by judges.
It can be but it’s still harder and the top Federal judges can be overruled by 3/4th majorities in the house and senate or by new constitutional amendments. Even a judge in this country in ignoring one part of the constitution still has to use other parts of the constitution to back up his reasoning or else get slapped down by higher courts on appeal. Now trial judges at local, state, or district fed court level are especially vulnerable to oversite should they overstep their bounds. A constitution always provides a shadowy influence that all can not totally ignore. A Federal judge is also dependent on the police forces and the bureaucracy to enforce their rulings and if his/her orders are so flagrantly illegal, they are apt to be ignored, held pending appeal, and the judge brought up on charges.
In Britain they have no such protections for the common people. A constitution provides a leavening influence acting between the naked potentially brutal direct power of government and the people “ruled or governed” by it.